Tracking of General and Abdominal Obesity in Children Between 4 and 9 Years of Age: The Longitudinal Childhood Obesity Study (ELOIN)

doi:10.21203/rs.3.rs-658635/v1

Background

A relationship between obesity early life has been reported. The aim of this study was to evaluate the variations in general (GO) and abdominal (AO) obesity between 4 and 9 years of age.

Methods

Children who participated in all three follow-ups at 4, 6 and 9 years participating in ELOIN study (N = 1902). Measurements of BMI and waist circumference were taken by physical examination. Prevalence ratios (PRs) were estimated by sex and family affluence by generalized estimation equation models, and the relative risks (RRs) of obesity by Poisson regression.

Results

The prevalence of GO was 5.1%, 9.1%, and 15.6% at 4, 6, and 9 years, yielding a PR between 9 − 4 years of 3.05 (95%CI: 2.58–3.60). The prevalence of AO was 6.8%, 8.4%, 14.5%, and the PR (9 vs 4y) was 2.14 (95%CI: 1.85–2.48). GO and AO presented an inverse correlation with family affluence. Among participants who were in GO or AO at 4 years, 77.3% and 63.6% remained in obesity after 5 years. The RRs of GO and AO at 9 years were 4.6 and 4.1 if they were obese at 4 years (p < 0.001), which increased to 9.4 and 9.5 in children obese at 6 years (p < 0.001), and those with obesity at both 4–6 years had RRs of 10.3 and 9.9 (p < 0.001).

Conclusions

GO and AO begin at early age, persist with age and linked with low socioeconomic status. Obesity at 9 years is associated with early obesity, either stably or intermittently, so preventive interventions should be established very early.

Health Economics & Outcomes Research

Infectious Diseases

Health Policy

general and abdominal obesity

waist circumference

children

tracking

Spain.

Childhood obesity continues to be a major public health problem in most countries¹. Globally, it was estimated that in 2016 there were 124 million young people between 5 and 19 years of age with obesity and 213 million overweight². In Europe, the prevalence of overweight and obesity in childhood is high, though there are large variations between regions, such as a higher prevalence in the Mediterranean basin³. In many countries, including Spain, there has been a trend towards stabilization in recent years³. According to the ALADINO study, the estimated prevalence for Spain in 2019 in the population aged 6 to 9 years was 23.3% and 17.3% for overweight and obese individuals⁴, respectively, quite similar to those observed in the same study in 2011 (26.2% and 18.3%, respectively)⁵.

Childhood obesity has been associated with higher blood pressure, myocardial dysfunction, dyslipidaemia, insulin resistance, fatty liver, stigmatization, and poor school performance^6,7. Its tendency to persist brings a greater risk of comorbidities in adulthood, such as diabetes, cardiovascular diseases, some types of cancer, and premature death^8,9.

General obesity (GO) is frequently defined by body mass index (BMI), which is a good predictor of cardiovascular risk¹⁰. In children, the relationship between BMI and body fat varies with age and sex and should be compared with standard or reference populations^11,12. Waist circumference (WC) is one of the parameters for diagnosing abdominal obesity (AO). It is defined from reference values and has a better correlation with subcutaneous and visceral fat than other indicators^13,14. Childhood AO is considered an important predictor of cardiometabolic disorders independent of BMI^15,16.

GO tends to start at an early age and persist over time. Children in overweight/obesity are more likely to remain in obesity in adolescence and to be in obesity in adults^17,18. AO also increases with age, but its longitudinal variations are less studied because the waist circumference is not routinely measured in primary-care paediatric programmes, and its validity is lower in children under 7 years¹⁴. More and more, there is consensus that in addition to BMI, it is necessary to monitor WC to detect its variations from childhood¹⁹.

We aimed to evaluate the risk of and track GO and AO in the child population between 4, 6, and 9 years old in a longitudinal study with 5 years of follow-up.

Study design and participants

The Longitudinal Childhood Obesity Study (ELOIN for its acronym in Spanish)) is a population-based cohort in the Madrid region (population 6,7 million), whose methods have been previously published²⁰. A total of 2627 4-year-old children were recruited for the baseline study.

In this analysis, 1902 participants underwent measurements at three physical examinations: the 4-year baseline measurement taken in 2012-2013, the 6-year in 2014-2015, and the 9-year in 2017-2018. The information was collected in two consecutive stages: 1) standardized physical examination performed in the health centre by paediatricians of the sentinel network and primary care nurses; and 2) completion of a structured questionnaire answered by the parents through a computer-assisted telephone interview (CATI), covering data on sociodemographic variables and lifestyles.

Anthropometric measures

Weight was measured with a digital scale (SECA® model 220, precision 0.1 kg), height was measured using a telescoping stadiometer (SECA® model 220, precision 1 mm), and WC was measured using a standardized inextensible locking measing tape just above the iliac crest with the tape horizontal and without tissue compression. Two measurements were made per participant, whose mean was taken for the analyses.

BMI (kg/m²) was adjusted by age (months) and sex according to the standardized tables of the WHO-2007¹¹. From the BMI z-scores, normal weight was defined as zBMI ≤ 1 standard deviation (SD), overweight zBMI > 1 SD and ≤ 2 SD, and GO when zBMI > 2 SD¹¹. WC was standardized by age (months) and sex according to reference tables of the International Diabetes Federation (IDF) metabolic syndrome consensus. To define AO, the ≥90 percentile was used as the cut-off point²¹.

Four GO trajectories were estimated, taking into account the persistence or variation in the classification of obesity at 4, 6, and 9 years: 1) Stable without obesity: no obesity in any of the measurements; 2) Remitting obesity at 9 years: obesity at 4 and/or 6 years, but without obesity at 9 years; 3) Incident obesity at 9 years (4 or 6): obesity only at 9 years, or at 4 and 9 years, or at 6 and 9 years; and 4) Stable with obesity: obesity in all three measurements. The same trajectories were used to evaluate the changes in AO.

Covariates

The sociodemographic variables, evaluated from the baseline measurements at 4 years old, were sex, age (months), and the household affluence estimated by the Family Affluence Scale, classified according to score as low (0–3 points), medium (4-5), and high (6-9)^22,23.

Data analysis

An initial descriptive analysis was performed, where the quantitative variables are summarized as mean (SD), and the qualitative variables are summarized as relative frequency. The statistical association between qualitative variables was calculated with the χ² test, and the comparisons of means were performed by Student’s t test. To facilitate the visual interpretation of the tracking, the flow diagrams were represented by a Sankey diagram. The prevalence ratios (PRs) were calculated using generalized estimating equation models under a binomial distribution. Then Poisson regression models were developed to estimate 1) the probability (relative risk, RR) of presenting GO and AO at 9 years based on obesity at 4-6 years of age and 2) the risk of GO at 6 and 9 years according to the presence of GO and/or AO at 4 years of age. The variables included sex, age (months), and family affluence. The interactions of the GO and AO indicators with sex and socioeconomic status were explored.

The analyses were performed in Stata v.16 (StataCorp, College Station, USA) taking into account the characteristics of cluster sampling (paediatric consultations) using the Survey Data module.

A total of 1902 participants who completed all three measurements were included, which represented 60% of the children with physical examination and 72.4% of those examined with a questionnaire in the baseline study. A total of 49.6% were male, and the mean (SD) ages at the 4, 6, and 9-year measurements were 48.5 (1.8), 73.4 (3.3), and 110.7 (4.5) months, respectively. The mean follow-up time was 5.2 years.

Table 1 shows that weight and height were higher in boys than in girls of all ages. BMI was higher in boys at 6 and 9 years, while WC was only higher in boys at 9 years. In the participants with low household affluence, the weight, BMI, and WC were higher than in those with high household affluence.

Table 1

Distribution of anthropometric values at 4, 6, and 9 years of age
	N	Age (months) Mean (SD)		p value	Weight (kg) Mean (SD)	p value	Height (cm) Mean (SD)	p value	BMI (kg/m²) Mean (SD)	p value	Waist (cm) Mean (SD)	p value
TOTAL
4 years	1902	48.5 (1.8)			16.9 (2.3)		103.4 (4.4)		15.8 (1.5)		51.8 (3.8)
6 years	1902	73.4 (3.3)			22.4 (4.1)		117.5 (5.3)		16.1 (2.0)		56.2 (5.6)
9 years	1902	110.9 (4.5)			33.6 (8.0)		136.2 (6.6)		18.0 (3.3)		64.7 (8.9)
AGE
4 years			0.035			< 0.001		< 0.001		0.215		0.430
Boys	944	48.6 (1.9)			17.1 (2.3)		104.0 (4.4)		15.8 (1.5)		51.7 (3.6)
Girls	958	48.4 (1.7)			16.7 (2.3)		102.9 (4.3)		15.7 (1.6)		51.9 (4.0)
6 years				0.990		< 0.001		< 0.001		0.025		0.050
Boys	944	73.4 (3.3)			22.7 (4.1)		118.0 (5.4)		16.2 (2.0)		56.2 (5.3)
Girls	958	73.4 (3.3)			22.1 (4.0)		117.1 (5.2)		16.0 (2.0)		56.2(5.8)
9 years				0.819		< 0.005		0.004		0.006		0.014
Boys	944	110.9 (4.5)			34.1 (8.1)		136.7 (6.4)		18.1 (3.5)		65.1 (9.0)
Girls	958	111.0 (4.5)			33.1 (7.8)		135.8 (6.7)		17.8 (3.0)		64.3 (8.7)
HOUSEHOLD AFFLUENCE
4 years				0.006		< 0.010		0.0666		< 0.010		< 0.001
Low	309	48.7 (2.2)			17.3 (2.7)		103.8 (4.6)		16.0 (1.8)		52.6 (4.4)
Medium	589	48.3 (1.6)			16.8 (2.3)		103.1 (4.1)		15.8 (1.5)		51.7 (3.8)
High	1004	48.5 (1.8)			16.9 (2.2)		103.5 (4.4)		15.7 (1.4)		51.6(3.6)
6 years				0.417		< 0.010		< 0.064		< 0.001		< 0.001
Low	309	73.5 (3.1)			23.0 (4.8)		117.1 (5.6)		16.5 (2.4)		57.4 (6.3)
Medium	589	73.2 (2.9)			22.2 (4.0)		117.1 (5.1)		16.1 (2.1)		56.2 (5.8)
High	1004	73.4 (3.4)			22.2 (4.0)		117.7(5.4)		16.0 (1.8)		55.9 (5.0)
9 years				0.352		< 0.001		0.274		< 0.001		< 0.001
Low	309	110.7 (4.1)			35.2 (9.2)		136.4 (7.0)		18.7 (3.6)		66.7 (9.8)
Medium	589	110.9 (4.1)			33.4 (8.3)		135.9 (6.5)		18.0 (3.6)		64.8 (9.3)
High	1004	111.1 (4.6)			33.2 (7.3)		136.4 (6.5)		17.7 (2.9)		64.0 (8.1)
BMI: body mass index. SD: standard deviation

Table 2 shows the evolution of the standardized prevalence of overweight, GO, and AO. The prevalence of overweight increased between 4 and 9 years of age, from 16.8–21.8% (PR: 1.30; 95% CI: 1.16–1.45; p < 0.001), with a similar evolution by sex (PR: 1.25 in boys; 1.35 in girls; p < 0.001) and by family affluence (PR: low affluence: 1.23; medium: 1.31; high: 1.31; p < 0.001). GO increased from 5.1–15.6% between 4 and 9 years (PR: 3.05; p < 0.001), in boys from 5.5–19.3% (PR: 3.50; p < 0.001), and in girls from 4.7–11.9% (PR: 2.53; p < 0.001). Likewise, an increase was observed in the population with low, medium, and high family affluence (PR: 2.81; 3.0, and 3.26, respectively; p < 0.001). At 6 and 9 years, the prevalence of GO was higher in boys (11.3% and 19.3%) than in girls (6.9 and 11.9%) and in those with low household affluence than high at 4, 6, and 9 years (8.7% vs 3.9%, 14.6% vs 7.1% and 24.6% vs 12.6%, respectively).

Table 2

Evolution of the prevalence of overweight, general obesity, and abdominal obesity at 4, 6, and 9 years of age by sex and household affluence

		Overweight^a						General obesity^b							Abdominal obesity^c
	N	%	95% CI	PR	95% CI	N			%	95% CI		PR	95% CI			N		%		95% CI	PR		95% CI
TOTAL
4 years	319	16.8	(15.2–18.5)	(ref)			97	5.1			(4.2–6.2)	(ref)			129		6.8		(5.7-8.0)			(ref)
6 years	326	17.1	(15.5–18.9)	1.02	(0.91–1.15)		173	9.1			(7.9–10.5)	1.78		(1.50–2.11)	160		8.4		(7.2–9.7)			1.24		(1.06–1.45)
9 years	414	21.8	(20.0-23.7)	1.30	1.16–1.45)		296	15.6			(14.0-17.3)	3.05		(2.58–3.60)	276		14.5		(13.0-16.2)			2.14		(1.85–2.48)
SEX
Boys
4 years	162	17.2	(14.9–19.7)	(ref)			52	5.5			(4.2–7.2)	(ref)			56		5.9		(4.6–7.6)			(ref)
6 years	175	18.5	(16.2–21.1)	1.08	(0.91–1.28)		107	11.3			(9.5–13.5)	2.06		(1.63–2.60)	70		7.4		(5.9–9.3)			1.25		(0.97–1.61)
9 years	202	21.5	(18.9–24.1)	1.25	(1.06–1.46)		182	19.3			(16.9–21.9)	3.50		(2.78–4.40)	136		14.4		(12.3–16.8)			2.43		(1.92–3.06)
Girls
4 years	157	16.4	(14.2–18.9)	(ref)			45	4.7			(3.5–6.2)	(ref)			73		7.6		(6.1–9.5)			(ref)
6 years	151	15.8	(13.6–18.2)	0.96	(0.81–1.14)		66	6.9			(5.4–8.7)	1.47		(1.14–1.89)	90		9.4		(7.7–11.4)			1.23		(1.00-1.51)
9 years	212	22.1	(19.6–24.9)	1.35	(1.16–1.58)		114	11.9			(9.8–14.1)	2.53		(1.99–3.22)	140		14.6		(12.5–17.0)			1.92		(1.58–2.32)
HOUSEHOLD AFFLUENCE
Low
4 years	51	16.5	(12.8–21.1)	(ref)			27	8.7			(6.1–12.5)	(ref)			36		11.6		(8.5–15.7)			(ref)
6 years	59	19.1	(15.1–23.9)	1.16	(0.85–1.56)		45	14.6			(11.0–19.0)	1.67		(1.21–2.28)	41		13.3		(10.0-17.5)			1.14		(0.85–1.52)
9 years	63	20.4	(16.2–25.3)	1.23	(0.92–1.66)		76	24.6			(20.1–29.7)	2.81		(2.08–3.82)	65		21.0		(16.8–25.9)			1.80		(1.38–2.36)
Medium
4 years	98	16.6	(13.8–19.9)	(ref)			31	5.3			(3.7–7.4)	(ref)			33		5.6		(4.0-7.8)			(ref)
6 years	92	15.6	(12.9–18.8)	0.94	(0.75–1.18)		57	9.7			(7.5–12.3)	1.84		(1.38–2.35)	53		9.0		(6.9–11.6)			1.62		(1.19–2.16)
9 years	129	21.7	(18.7–25.4)	1.31	(1.06–1.60)		93	15.8			(13.0–19.0)	3.00		(2.26–3.98)	91		15.4		(12.7–18.6)			2.75		(2.07–3.66)
High
4 years	170	16.9	(14.7–19.4)	(ref)			39	3.9			(2.8–5.3)	(ref)			60		6.0		(4.7–7.6)			(ref)
6 years	175	17.4	(15.2–19.9)	1.03	(0.88–1.21)		71	7.1			(5.6–8.8)	1.82		(1.37–2.42)	66		6.6		(5.2–8.3)			1.10		(0.860–1.41)
9 years	223	22.2	(19.7–24.9)	1.31	1.13–1.52)		127	12.6			(10.7–14.8)	3.26		(2.47–4.28)	120		11.9		(10.1–14.1)			2.00		(1.59–2.50)

^a Overweight: BMI >1 standard deviation (SD) and ≤2 SD over the values in the WHO-2007 standardized tables

^b Obesity: BMI >2 (SD) according to the WHO-2007 standardized tables

^c Abdominal obesity: ≥90th percentile of waist circumference according to the consensus of the international Diabetes Foundation (IDF)²¹

PR: prevalence ratio; 95% CI: 95% confidence interval

The AO rate increased between 4 and 9 years of age from 6.8–14.5% (PR: 2.14; p < 0.001), with a fairly similar trend by sex (PR: 2.43: p < 0.001 in boys and PR: 1.92; p < 0.001 in girls) and family affluence, where the prevalence of AO was approximately twice as high in those of lower socioeconomic status as those of a high level.

Regarding the variations in obesity (Table 3), 82.4% and 82.1% of the participants remained without GO and AO, respectively; 12.1% (GO) and 11% (AO) had incident obesity; and 3.4% (GO) and 3.5% (AO) remained with obesity. The prevalence of stable boys without GO (78.6%) was lower than that of girls (86.1%). Participants with poorer socioeconomic status showed a higher prevalence of stable GO (6.2%) and AO (6.5%) than those of high status (2.3% for GO and 2.5% for AO), with children from medium-affluence households in an intermediate position.

Table 3

Variations in the prevalence of general and abdominal obesity in 4-, 6-, and 9-year-olds by sex and household affluence

Obese BMI or abdominal obesity	N	%	95% CI	N	%	95% CI
TOTAL
Stable without obesity^c	1.567	82.4	(80.6–84.0)	1562	82.1	(80.3–83.8)
Remitting obesity at 9 years^d	39	2.1	(1.5–2.8)	64	3.4	(2.6–4.3)
Incident obesity at 9 and (4 or 6)^e	230	12.1	(10.7–13.6)	209	11.0	(9.6–12.5)
Stable with obesity^f	66	3.4	(2.7–4.4)	67	3.5	(2.8–4.5)
SEX
Boys
Stable without obesity^c	742	78.6	(75.9–81.1)	780	82.6	(80.1–84.9)
Remitting obesity at 9 years^d	20	2.1	(1.4–3.3)	28	3.0	(2.1–4.3)
Incident obesity at 9 and (4 or 6)^e	145	15.4	(13.2–17.8)	112	11.9	(10.0–14.1)
Stable with obesity^f	37	3.9	(2.9–5.4)	24	2.5	(1.7–3.8)
Girls
Stable without obesity^c	825	86.1	(83.8–88.2)	782	81.6	(79.0–84.0)
Remitting obesity at 9 years^d	19	2.0	(1.3–3.1)	36	3.8	(2.7–5.1)
Incident obesity at 9 and (4 or 6)^e	85	8.9	(7.2–10.8)	97	10.1	(8.3–12.2)
Stable with obesity^f	29	3.0	(2.1–4.3)	43	4.5	(3.3-6.0)
HOUSEHOLD AFFLUENCE
Low
Stable without obesity^c	226	73.1	(67.9–77.8)	229	73.0	(68.9–78.7)
Remitting obesity at 9 years^d	7	2.3	(1.1–4.7)	15	5.4	(2.9–7.9)
Incident obesity at 9 and (4 or 6)^e	57	18.5	(14.5–23.2)	45	15.1	(11.0–19.0)
Stable with obesity^f	19	6.2	(3.9–9.5)	20	6.5	(4.2–9.8)
Medium
Stable without obesity^c	487	82.7	(79.4–85.5)	484	82.1	(78.9–85.1)
Remitting obesity at 9 years^d	9	1.5	(0.8–2.9)	14	2.5	(1.4–4.0)
Incident obesity at 9 and (4 or 6)^e	69	11.7	(9.4–14.6)	70	12.0	(9.5–14.8)
Stable with obesity^f	24	4.1	(2.7–6.0)	21	3.4	(2.3–5.4)
High
Stable without obesity^c	854	85.1	(82.7–87.1)	849	84.8	(82.2–86.7)
Remitting obesity at 9 years^d	23	2.3	(1.5–3.4)	35	3.4	(2.5–4.8)
Incident obesity at 9 and (4 or 6)^e	104	10.4	(8.6–12.4)	94	9.3	(7.7–11.3)
Stable with obesity^f	23	2.3	(1.5–3.4)	26	2.5	(1.8–3.8)
^aGeneral obesity: BMI > 2 SD over the values in the WHO-2007 standardized tables
^bAbdominal obesity: ≥90th percentile of waist circumference according to the consensus of the International Diabetes Federation (IDF)²¹
^cNo obesity in any of the measurements; ^dobesity at 4 and/or 6 years but no obesity at 9 years; ^eobesity only at 9 years, 4 and 9 years, or 6 and 9 years; ^fobesity in all three measurements
95% CI: 95% confidence interval

The Sankey diagram (Fig. 1) showed the tracking over the three measurements (see also Fig. 1S and 2S of supplementary material), highlighting that 77.3% of children with GO at 4 years old and 85,5% at 6 years old maintained GO at 9 years old. Only 1–3% remitted to normal weight. Of those classified with obesity at 9 years, approximately half were incident cases.

Table 4 shows that, with respect to stable patients without obesity, patients had a RR of GO at 9 years of 4.61 (95% CI: 2.35–9.06) if they were obese at age 4 but not age 6; 9.36 (95% CI: 7.09–12.36) if obese at 6 years but not at 4; and 10.27 (CI95: 7.63–13.81) if obese at 4 and 6 years. Similar results were found for the risk of presenting AO at 9 years, with estimated RRs of 4.14 (95% CI: 2.42–7.08), 9.56 (95% CI 7.04–12.98) and 9.88 (95% CI: 7.32–13.33), respectively.

Table 4

Risk of general and abdominal obesity at 9 years of age according to the presence of obesity at 4 and 6 years of age
	General obesity^a at 9 years			Abdominal obesity^b at 9 years
	N	RR^c	95% CI	N	RR^c	95% CI
Obesity 4 and 6 years
Stable without obesity at 4 and 6 years	1706	(ref)		1696	(ref)
Obesity at 4, not at 6 years	23	4.61	(2.35–9.06)	46	4.14	(2.42–7.08)
No obesity at 4, obesity at 6 years	99	9.36	(7.09–12.36)	77	9.56	(7.04–12.98)
Obesity at 4 and 6 years	74	10.27	(7.63–13.81)	83	9.88	(7.32–13.33)
^a General obesity: BMI > 2 SD over the values in the WHO-2007 standardized tables
^b Abdominal obesity: ≥90th percentile of waist circumference according to the consensus of the International Diabetes Federation (IDF)²¹
^c Relative risk estimated by Poisson regression and adjusted for age, sex, and household affluence
95% CI: 95% confidence interval

Finally (see Table 5), participants with joint obesity (GO and AO) at 4 years old had RRs of 16.10 (95% CI: 11.29–22.92) and 6.53 (95% CI: 4.79–8.91) for GO at 6 and 9 years, respectively, compared to children without obesity at 4 years old. Those who at 4 years old had only GO had RRs of 12.37 (95% CI: 7.64–20.06) and 5.64 (95% CI: 3.63–8.78) for an obese BMI at ages 6 and 9 compared to those who had AO but not GO, respectively.

Table 5

Risk of general obesity at 6 and 9 years of age according to the presence of general obesity and/or abdominal obesity at 4 years of age
		General obesity^a at 6 years		General obesity at 9 years
Obesity 4 years	N	RR^c	95% CI	RR^c	95% CI
No obese BMI/No abdominal obesity	1741	(ref)		ref
Obese BMI/No abdominal obesity	32	12.37	(7.64–20.06)	5.64	(3.63–8.78)
No obese BMI/Abdominal obesity	64	5.19	(3.00-9.01)	3.14	(2.02–4.90)
Obese BMI/Abdominal obesity^b	65	16.10	(11.29–22.92)	6.53	(4.79–8.91)
^a General obesity: BMI > 2 SD over the values in the WHO-2007 standardized tables
^b Abdominal obesity: ≥90th percentile of waist circumference according to the consensus of the International Diabetes Federation (IDF)²¹
^c Relative risk estimated by Poisson regression and adjusted for age, sex, and household affluence
95% CI: 95% confidence interval

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</table>

This study describes the tracking of overweight and obesity using longitudinal data from a child cohort followed from 4 to 9 years of age. The high increase in GO and AO stands out, with prevalences three-fold and two-fold higher at 9 years old than 4 years old. This increase is due to the large number of incident cases compared to the low remission percentage and is observed for all socioeconomic levels, although the prevalence is twice as high in those with low household affluence. It is very important to detect obesity early, since its appearance at 4 or 6 years determines obesity at 9 years. The two indicators of obesity (GO and AO) are complementary, and their combined use in young children maximizes the detection of obesity.

Most studies show that GO increases until 9–10 years and in adolescence decreases until the beginning of adulthood^1,2. In our study, the evolution of the prevalence of overweight and GO from 4 to 9 years of age were of similar magnitude and trend with respect to other cross-sectional studies of our environment^5,24. In the measurements at 6 and 9 years, we estimated a higher prevalence of GO in boys than in girls. This difference may be due not so much to environmental or behavioural factors but instead to hormonal changes, adiposity rebound, and distribution of body and muscle fat, which vary with age and sex^25,26.

In our study, the prevalence of AO increased with age and was similar to that observed by Schröeder et al.²⁷ and lower than the recent data by Aranceta-Bartrina, which estimated a prevalence of 21.5%²⁴. These differences could be explained by the different measurement criteria and cut-off points of the WC used to define AO; we chose the IDF consensus that allows for international comparisons²¹. International organizations should make an effort to have international reference populations given their importance in the detection of cardiometabolic risk from an early age.

Regarding socioeconomic status, in Western countries, childhood obesity follows a clear gradient, with a higher prevalence in children with lower socioeconomic status²⁸. However, it is not clear that these differences are maintained or continue to increase, because while some studies describe increasing inequality, others note a fairly uniform evolution²⁹. We found higher prevalences in children with low household affluence, though the age 4–9 growth trends of both GO and AO were similar in low-, medium-, and high-affluence children. In Spain, great disparity in numbers has been observed. The study by Albaladejo-Vicente et al.³⁰ based on the national health survey from 1997 to 2017 examined the population aged 5–15 years, showing a decreasing trend of obesity in children of parents of low socioeconomic status, while in girls, the trend was increasing. In a study from Andalusia, the social gradient of childhood obesity by socioeconomic indicators observed in 2011–2012 disappeared by 2015-2016³¹. However, a study conducted in Catalonia based on primary care electronic medical records noted an increase in inequality (estimated ecologically) between 2006 and 2016³².

On the other hand, our estimates are consistent with studies suggesting that obesity frequently begins early on and that children with GO and AO tend to stay obese^33,34. Children with or without GO at 4 or 6 years in our study tended to remain in the same category at 9 years. We also found that the risk of obesity at 9 years was greater if they had been obese at 4 and 6 years than if they had been obese at only one of the previous measurements. Similar results were reported by other studies, such as the one carried out in Norway, where children with excess weight at 2–4 years had an 11 times higher risk (odds ratio) of being overweight at 5–7 years than children with normal weight³⁵. In Australia, 5-year-old children who were obese were 25 times more likely to be obese 3 years later than those who were not obese³⁶.

To compare the variations and risk of AO, little information is available for this age group in Spain or in other countries. Vogelezang et al.³⁴ found that the persistence of AO was very high at early ages. A recent study by Ochiai et al.³⁷ estimated that half of the children classified with AO remained in the same category in adolescence. We observed even greater persistence of AO; 60–80% of obese children at 4 or 6 years old remained in the same category at 9 (see supplementary material), and the risk of AO at 9 years was 10 times higher if the child had been obese at both 4 and 6 years. These results are in line with other studies, but comparisons should be made with caution given the differences in follow-up time, ages, and classification methods used^38,39.

A relevant aspect of important public health implications is the greater probability of having GO at 6 or 9 years in those children who at 4 had AO, but not GO, which represented 3.4% of our analysed children. Considering that children with a normal weight and BMI but with AO have a high cardiometabolic risk, the combined measurement of weight, height, and WC will improve the predictive power to detect this health problem⁴⁰.

To correctly interpret the results of the study, several limitations must be taken into account. On the one hand, we do not have information on the weight status between birth and 4 years, which prevents the completion of the children’s obesity trajectories. In the constitution of the ELOIN cohort, a moderate bias was observed in the selection of the sample that would affect its population representativeness: children with low educational level and foreign parents had a lower response rate at the baseline measurement²⁰. However, those who participated in the three follow-up measurements maintained their similarity with respect to the sociodemographic variables of the baseline cohort.

As strengths, we highlight the longitudinal design of the study. In addition, the sample is representative of the population of Community of Madrid, even with the selection bias mentioned above. Anthropometric measurements are based on objective criteria and were performed in a standardized way in all measurements, so they are subject to fewer validity errors, such as self-reported measures or those provided by parents⁴¹.

In conclusion, GO and AO begin at an early age, are associated with low socioeconomic status, and increase rapidly with age. Obesity at 9 years is closely correlated with having previously been obese, either stably or intermittently, so prevention and management interventions should be established very early. The combined use of GO and AO indicators maximizes the detection of this health problem.

This study provides recent data on the variations in the prevalence of general and abdominal obesity, in a representative cohort of Community of Madrid, followed from 4 to 9 years of age. The prevalence of general obesity at 9 years is 3 times higher than at 4 years, with a 2-fold increase in abdominal obesity.

General and abdominal obesity begin at an early age, are associated with low socioeconomic status, and increase rapidly with age. Obesity at 9 years is closely correlated with having previously been in obesity, either stably or intermittently, so prevention and management interventions should be established very early. The two indicators of general and abdominal obesity are complementary, and their joint use could maximize the detection and control of this health problem.

BMI

body mass index; CI:confidence interval; RR:relative risk; SD:standard deviation; WC:Waist circumference; AO:Abdominal obesity; GO:General obesity; WHO:World Health Organization. IDF:International Diabetes Foundation; ELOIN:Longitudinal Childhood Obesity Study.

Ethics approval and consent to participate

The Ethics Committee of the Ramón y Cajal Hospital in Madrid approved the study (CIHURC- 122/11). Prior participation, all participants provided written informed consent. Written informed consent was obtained from their parents or legal guardians. The current study was conducted according to the Declaration of Helsinki and all methods were performed in accordance with the relevant guidelines and regulations.

Consent for publication

Not applicable.

Availability of data and material

According to private and confidential clauses states in the informed consent, the dataset generated an analysed during the current study is ethically restricted and not publicly available. It would be available from Dr. Honorato Ortiz-Marrón (E-mail: [email protected]) on reasonable request.

Competing interest

The authors declare that there are no potential conflicts of interest regarding the research, authorship and/or publication of this article.

Funding

The ELOIN study is funded by the General Directorate of Public Health of the Ministry of Health of the Community of Madrid. The authors have not received financial support for the research, authorship, or publication of this article. This project received a grant for the translation and publication of this paper from the Foundation for Biosanitary Research and Innovation in Primary Care (FIIBAP).

Autors’ contributions

H Ortiz-Marrón and I Galán conceptualized and designed the study, developed the initial manuscript with tables and figures, and checked and revised the final manuscript. H Ortiz-Marrón, I Galán, and MA Ortiz-Pinto designed the instruments for data collection, data collection, and initial analysis. MA Ortiz-Pinto, JG Martínez Mosquera, M Lorente Miñarro ^c, F Menchero Pinos, and M Ordobás Gavín participated in the data collection and critically reviewed the manuscript by making important contributions to its content. All authors gave their approval to the final manuscript and agreed and assume responsibility for all aspects of the work.

Acknowledgments

To the participating families, to the health workers and to the companies Demométrica, Sondaxe, and Sigmados, who conducted the telephone interviews.

Seidell JC, Halberstadt J. The global burden of obesity and the challenges of prevention. Ann Nutr Metab. 2015;66 Suppl 2:7–12.
NCD Risk Factor Collaboration (NCD-RisC). Worldwide trends in body-mass index, underweight, overweight, and obesity from 1975 to 2016: a pooled analysis of 2416 population-based measurement studies in 128·9 million children, adolescents, and adults. Lancet. 2017;390(10113):2627–42.
Garrido-Miguel M, Cavero-Redondo I, Álvarez-Bueno C, Rodríguez-Artalejo F, Moreno LA, Ruiz JR, et al. Prevalence and Trends of Overweight and Obesity in European Children From 1999 to 2016: A Systematic Review and Meta-analysis. JAMA Pediatr. 2019;e192430. doi:10.1001/jamapediatrics.2019.2430.
Agencia Española de Seguridad Alimentaria y Nutrición. Ministerio de Consumo, 2020. Estudio Aladino 2019: Estudio sobre alimentación, actividad física, desarrollo infantil y obesidad en España 2019. Available from: https://www.aesan.gob.es/AECOSAN/web/nutricion/detalle/aladino_2019.htm.
García-Solano M, Gutiérrez-González E, López-Sobaler AM, Dal Re Saavedra MÁ, Robledo de Dios T, Villar-Villalba C, et al. Weight status in the 6 to 9 year-old school population in Spain: Results of the ALADINO 2015 Study. An Pediatr. 2020. doi:10.1016/j.anpedi.2020.05026
Han JC, Lawlor DA, Kimm SYS. Childhood Obesity-2010: Progress and Challenges. Lancet. 2010;375(9727):1737–48.
Puhl RM, Lessard LM. Weight Stigma in Youth: Prevalence, Consequences, and Considerations for Clinical Practice. Curr Obes Rep. 2020;9(4):402–411.
Umer A, Kelley GA, Cottrell LE, Giacobbi P, Innes KE, Lilly CL. Childhood obesity and adult cardiovascular disease risk factors: a systematic review with meta-analysis. BMC Public Health. 2017;17(1):683. doi:10.1186/s12889.017.4691.z.
Llewellyn A, Simmonds M, Owen CG, Woolacott N. Childhood obesity as a predictor of morbidity in adulthood: a systematic review and meta-analysis. Obes Rev. 2016;17(1):56–67.
Freedman DS, Sherry B. The validity of BMI as an indicator of body fatness and risk among children. Pediatrics. 2009;124 Suppl 1:S23-34.
de Onis M, Onyango AW. WHO child growth standards. Lancet. 2008;371(9608):204–214.
Cole TJ, Bellizzi MC, Flegal KM, Dietz WH. Establishing a standard definition for child overweight and obesity worldwide: international survey. BMJ. 2000;320(7244):1240–3.
Orsso CE, Silva MIB, González MC, Rubin DA, Heymsfield SB, Prado CM, et al. Assessment of body composition in pediatric overweight and obesity: A systematic review of the reliability and validity of common techniques. Obes Rev. 2020;21(8):e13041. doi:10.1111/obr.13041.
Brambilla P, Bedogni G, Moreno LA, Goran MI, Gutin B, Fox KR, et al. Crossvalidation of anthropometry against magnetic resonance imaging for the assessment of visceral and subcutaneous adipose tissue in children. Int J Obes (Lond). 2006;30(1):23–30.
Fox CS, Massaro JM, Hoffmann U, Pou KM, Maurovich-Horvat P, Liu C-Y, et al. Abdominal visceral and subcutaneous adipose tissue compartments: association with metabolic risk factors in the Framingham Heart Study. Circulation. 2007;116(1):39–48.
Song Q, Huang T, Song J, Meng X, Li C, Wang Y, et al. Causal associations of body mass index and waist-to-hip ratio with cardiometabolic traits among Chinese children: A Mendelian randomization study. Nutr Metab Cardiovasc Dis. 2020;30(9):1554–63.
Simmonds M, Llewellyn A, Owen CG, Woolacott N. Predicting adult obesity from childhood obesity: a systematic review and meta-analysis. Obes Rev. 2016;17(2):95–107.
Bayer O, Krüger H, von Kries R, Toschke AM. Factors associated with tracking of BMI: a meta-regression analysis on BMI tracking. Obesity (Silver Spring). 2011;19(5):1069–76.
US Preventive Services Task Force, Grossman DC, Bibbins-Domingo K, Curry SJ, Barry MJ, Davidson KW, et al. Screening for Obesity in Children and Adolescents: US Preventive Services Task Force Recommendation Statement. JAMA. 2017;317(23):2417–26.
Ortiz-Marrón H, Cuadrado-Gamarra JI, Esteban-Vasallo M, Cortés-Rico O, Sánchez-Díaz J, Galán-Labaca I. The Longitudinal Childhood Obesity Study (ELOIN): Design, Participation and Characteristics of the Baseline Sample. Rev Esp Cardiol. 2016;69(5):521–3.
Zimmet P, Alberti KGM, Kaufman F, Tajima N, Silink M, Arslanian S, et al. The metabolic syndrome in children and adolescents - an IDF consensus report. Pediatr Diabetes. 2007;8(5):299–306.
Torsheim T, Cavallo F, Levin KA, Schnohr C, Mazur J, Niclasen B, et al. Psychometric Validation of the Revised Family Affluence Scale: a Latent Variable Approach. Child Indic Res. 2016;9:771–84.
ter Bogt TFM, de Looze M, Molcho M, Godeau E, Hublet A, Kokkevi A, et al. Do societal wealth, family affluence and gender account for trends in adolescent cannabis use? A 30 country cross-national study. Addiction. 2014;109(2):273–83.
Aranceta-Bartrina J, Gianzo-Citores M, Pérez-Rodrigo C. Prevalence of overweight, obesity and abdominal obesity in the Spanish population aged 3 to 24 years. The ENPE study. Rev Esp Cardiol. 2020;73(4):290–9.
Fomon SJ, Haschke F, Ziegler EE, Nelson SE. Body composition of reference children from birth to age 10 years. Am J Clin Nutr. 1982;35(5 Suppl):1169–75.
Williams SM, Goulding A. Patterns of growth associated with the timing of adiposity rebound. Obesity (Silver Spring). 2009;17(2):335–41.
Schröder H, Ribas L, Koebnick C, Funtikova A, Gomez SF, Fíto M, et al. Prevalence of abdominal obesity in Spanish children and adolescents. Do we need waist circumference measurements in pediatric practice? PLoS One. 2014;9(1):e87549. doi:10.1371/journal.pone.0087549
McLaren L. Socioeconomic status and obesity. Epidemiol Rev. 2007;29(1):29–48.
Chung A, Backholer K, Wong E, Palermo C, Keating C, Peeters A. Trends in child and adolescent obesity prevalence in economically advanced countries according to socioeconomic position: a systematic review. Obes Rev. 2016;17(3):276–95.
Albaladejo-Vicente R, Villanueva-Orbaiz R, Carabantes-Alarcon D, Santos-Sancho J, Jiménez-García R, Regidor E. Reversal of the Upward Trend of Obesity in Boys, but Not in Girls, in Spain. Int J Environ Res Public Health. 2021;18(4). doi:10.3390/ijerph18041842
Sánchez-Cruz J-J, de Ruiter I, Jiménez-Moleón JJ, García L, Sánchez M-J. Stabilization and reversal of child obesity in Andalusia using objective anthropometric measures by socioeconomic status. BMC Pediatr. 2018;18(1):322. doi:10.3390/ijerph18041842
de Bont J, Díaz Y, Casas M, García-Gil M, Vrijheid M, Duarte-Salles T. Time Trends and Sociodemographic Factors Associated With Overweight and Obesity in Children and Adolescents in Spain. JAMA Netw Open. 2020;3(3):e201171. 10.1001/jamanetworkopen.2020.1171
Wheaton N, Millar L, Allender S, Nichols M. The stability of weight status through the early to middle childhood years in Australia: a longitudinal study. BMJ Open. 2015;5(4):e006963. doi:10.1136/bmjopen-2014-006963
Vogelezang S, Gishti O, Felix JF, van der Beek EM, Abrahamse-Berkeveld M, Hofman A, et al. Tracking of abdominal subcutaneous and preperitoneal fat mass during childhood. The Generation R Study. Int J Obes (Lond). e 2016;40(4):595–600.
Evensen E, Wilsgaard T, Furberg A-S, Skeie G. Tracking of overweight and obesity from early childhood to adolescence in a population-based cohort - the Tromsø Study, Fit Futures. BMC Pediatr. 2016;16:64. doi: 10.1186/s12887-016-0599-5.
Hesketh K, Wake M, Waters E, Carlin J, Crawford D. Stability of body mass index in Australian children: a prospective cohort study across the middle childhood years. Public Health Nutr. 2004;7(2):303–9.
Ochiai H, Shirasawa T, Nishimura R, Yoshimoto T, Minoura A, Oikawa K, et al. Changes in overweight/obesity and central obesity status from preadolescence to adolescence: a longitudinal study among schoolchildren in Japan. BMC Public Health. 2020;20(1):241. doi:10.1186/s12889-020-8343-3.
Cunningham SA, Datar A, Narayan KMV, Kramer MR. Entrenched Obesity in Childhood: Findings from a National Cohort Study. Ann Epidemiol. 2017;27(7):435–41.
Geserick M, Vogel M, Gausche R, Lipek T, Spielau U, Keller E, et al. Acceleration of BMI in Early Childhood and Risk of Sustained Obesity. N Engl J Med. 2018;379(14):1303–12.
Gishti O, Gaillard R, Durmus B, Abrahamse M, van der Beek EM, Hofman A, et al. BMI, total and abdominal fat distribution, and cardiovascular risk factors in school-age children. Pediatric Research. 2015;77(5):710–8.
Esteban-Vasallo MD, Galán I, Ortiz-Pinto MA, Astray San Martín A, Cabrero López EM, Morales San José MT, et al. Accuracy of anthropometric measurements and weight status perceptions reported by parents of 4-year-old children. Public Health Nutr. 2019;1–10.

No competing interests reported.

Supplementarylnformation.docx

Tracking of General and Abdominal Obesity in Children Between 4 and 9 Years of Age: The Longitudinal Childhood Obesity Study (ELOIN)

Status:

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Abstract

Background

Methods

Results

Conclusions

Figures

Background

Methods

Results

Discussion

Conclusions

List Of Abbreviations

Declarations

References

Additional Declarations

Supplementary Files

Status:

Version 1