Associations between serum vitamin D levels and visceral adipose tissue among adolescents: a cross-sectional observational study in NHANES 2011-2015

doi:10.21203/rs.3.rs-1619161/v1

Backgrounds:

The incidence of obesity and vitamin D deficiency increases among adolescents. Improving our knowledge of the link between vitamin D and visceral adipose tissue (VAT) is essential for the health of adolescents. This study aimed to examine the connection between blood vitamin D levels and VAT mass among adolescents participating in the United States.

Methods

This is a cross-sectional study that used data from the 2011 to 2015 National Health and Nutrition Examination Survey (NHANES). The connection between blood vitamin D levels and VAT was investigated using weighted multiple linear regression models. Potential nonlinear relationships were explored using smooth curve fitting.

Results

An overall number of 3171 adolescents between the ages of 12 and 19 were recruited to take part in this research. Vitamin D levels were shown to be inversely linked with VAT in the full-adjusted model (β= -0.38, 95% CI: -0.53 to -0.23). When subgroup analysis was stratified by gender, this negative connection remainder in the girls' group (β= -0.44, 95% CI: -0.65 to -0.22), but not in the boys' group (β= -0.07, 95% CI: -0.26 to 0.12). When subgroup analysis was stratified by race, this negative connection remained in the Mexican American group (β= -0.63, 95% CI: -1.04 to -0.21), and the non-Hispanic White group (β= -0.35, 95% CI: -0.62 to -0.08), but not in the other groups.

Conclusions

In this investigation, it was shown that serum vitamin D levels negatively correlated with VAT in girls, the Mexican American and non-Hispanic White in adolescents.

Vitamin D

visceral adipose tissue

Adolescent

NHANES

Obesity is a multifactorial state of chronic excess fat accumulation linked to serious health risks[1]. Obesity leads to insulin resistance, diabetes, and hypertension, greatly increasing cardiovascular disease (CVD) morbidity and mortality[2, 3]. It has been demonstrated that abdominal fat deposition is superior to whole-body fat in predicting coronary artery risk[4]. Furthermore, the Framingham heart study confirmed that stronger association of visceral adipose tissue (VAT) with some common cardiovascular and metabolic risk variables than subcutaneous adipose tissue (SAT)[5].

Vitamin D's primary function is to keep calcium metabolism in check and preserve bone health[6]. In addition, serum vitamin D has a critical role in many prevalent chronic conditions, including CVD, metabolic syndrome, obesity, insulin resistance, prediabetes and type 2 diabetes[7–9]. According to a meta-analysis, vitamin D is inversely connected to cardiovascular risk[10].

Numerous researches have long identified a relationship between the lack of vitamin D and obesity[11–13]. Because of VAT playing an important function in the cardiovascular system[5], some scholars have explored the link between serum vitamin D levels and visceral fat. Two large-scale epidemiological surveys have reported a negative link between VAT thickness and serum vitamin D concentration in adults[14, 15]. However, the correlation between VAT and blood vitamin D is uncertain in adolescents. This study explored the correlation between the two in American adolescents using a multi-ethnic population database sample.

Study population

The National Health and Nutrition Examination Survey (NHANES) is a nationally representative survey that gathers health screening information from the U.S. non-institutionalized population[16]. The nationwide study is conducted every two years, continuously. The data used in this study are from three consecutive NHANES cycles from 2011 to 2016. As shown in Figures 1, this study included 3171 subjects who had complete information on blood vitamin D levels and VAT mass aged between 12-19. The NHANES procedure was approved by the Institutional Review Committee of the National Center for Health Statistics, and all participants or their agents (< 18 years old) completed the informed permission froms[17, 18].

Variables

The dependent variable was VAT mass in this study, and all included participants were given whole-body scans using dual-energy X-ray absorptiometry (DXA). In the 2011–2016 cycles, VAT mass was assessed by qualified and certified radiation technologists using the DXA scans obtained from the Hologic Discovery model A densitometer (Hologic, Inc., Bedford, Massachusetts, software version Apex 3.2).

The independent variable in this study was blood vitamin D levels obtained by the radioimmunoassay kit (DiaSorin, Stillwater, Minnesota, USA) during the 2011–2016 cycles. In addition, blood vitamin D levels were split into three main categories: deficiency (<50 nmol/L), insufficient (50-75 nmol/L), and sufficient (≥75 nmol/L)[19].

According to previous studies[20, 21], age, sex, race, sedentary activity, income-to-poverty ratio, six-month time of detection, and body mass index(BMI) were identified as potential confounding factors. All details about serum vitamin D levels, VAT mass, and other variables are recorded at www.cdc.gov/nchs/nhanes/.

Statistical analysis

According to NHANES's recommendation, all analyses used the sample weights derived from designs based on stratified, multistage probabilistic sampling. For categorical and continuous variables, P values were obtained using the weighted chi-square test and the linear regression model, respectively. And two-sided P-value less than 0.05 was deemed statistically significant. The weighted multiple linear regression models adjusted for different confounders were performed to explore whether serum vitamin D levels were independently related to VAT mass. In addition, subgroup analysis was carried out to assess the impact of gender or race on the outcome. The potential nonlinear relationship was explored by smooth curve fitting. All data analyses were performed using EmpowerStats (http://www.empowerstats.com) and the R software (version 3.5.3).

As shown in Table 1, this study included 3,171 eligible adolescents with weighted characteristics divided into three categories: deficiency, insufficiency, and sufficiency. Participants in different groups differed significantly in baseline characteristics. Compared to the deficient group, participants in the insufficiency and sufficiency groups increased income-to-poverty ratio, but decreased sedentary activity, BMI, waist circumference, and VAT mass.

As shown in Table 2, the relation between serum vitamin D levels and VAT mass was negatively correlated in all multivariate linear regression models (β= -0.38, 95% CI: -0.53 to -0.23). In addition, the trend was still obvious in different groups (P for trend <0.001). When subgroup analysis was stratified by gender, this negative connection remainder in the girls' group (β= -0.44, 95% CI: -0.65 to -0.22), but not in the boys' group (β= -0.07, 95% CI: -0.26 to 0.12). When subgroup analysis was stratified by race, this negative connection remained in the Mexican American group (β= -0.63, 95% CI: -1.04 to -0.21) and the non-Hispanic White group (β= -0.35, 95% CI: -0.62 to -0.08), but not in the other groups.

As shown in Figures 2-3, the smooth curve fitting and generalized addition model illustrated the nonlinear correlation between serum vitamin D levels and VAT mass.

This study aimed to explore whether there is an independent link between blood vitamin D concentrations and VAT in adolescents. Our study analyzed their association using NHANES data, and found that VAT mass decreased with the increase of serum vitamin D levels in American adolescents.

Evidence suggests that the metabolism, storage, and function of vitamin D can affect obesity and be affected by obesity. Some researches have shown that obesity is prone to vitamin D insufficiency^21–23, which may be because people of obesity have more VAT, which can store more vitamin D[22]. This may have resulted in less vitamin D being released into the bloodstream, so these people had lower serum vitamin D levels. Reduced outdoor exercise and increased clothing covering the skin also reduced the photochemical subcutaneous production of vitamin D in overweight people[23]. Meanwhile, a deficiency of vitamin D can lead to obesity. There are shreds of evidence that vitamin D deficiency promotes body fat production, which may be due to the flow of calcium into adipocytes by increasing parathyroid hormone synthesis[24, 25]. Although this study discovered a connection between VAT mass and low vitamin D levels, it was just an observational study. It was unable to demonstrate a temporal relationship between VTA mass and low vitamin D.

Fat distribution affects obesity outcomes, and the increase in visceral fat can affect people's health[5, 26, 27]. Most studies on the link between VAT and vitamin D levels come from adult data. The Framingham Heart Study[14] reported that people with high VAT were more deficient in vitamin D than those with low VAT. Other studies had come to a similar conclusion that VAT was inversely associated with serum vitamin D levels[15, 28]. However, there is currently little research on VAT and vitamin D in adolescents. In a small cross-sectional cohort(n = 58), the researchers discovered an independent negative connection between VAT and serum 25(O.H.)D levels in individuals of obesity aged 13-17.9y enrolled from five geographic regions in Boston[21]. In another medium-sized study (n = 559), the concentration of 25-hydroxyvitamin D was shown to be substantially adversely linked with visceral fat in adolescents aged 14-18y in Atlanta[29]. These studies are the same as ours; our data(n = 3712) confirm this relationship between VAT and vitamin D among 12-19y in the United States.

It is well recognized that obesity levels and body fat distribution vary across races and ethnicities[30–33]. For the same BMI, Caucasian children are more obese than African-American children[31]. Additionally, abdominal adipose tissue is distributed differently by ethnicity: a survey of 237 8–18 years old living in Pennsylvania found that Caucasian children have higher VAT and lower SAT than African-American children[20]. The same study also suggested that lower vitamin D concentrations were linked to higher VAT levels among the white but not among the black[20]. Like the studies above, we also found that the link between vitamin D and VAT differed between black and white. Although ethnic differences in the extent of vitamin D accumulation in adipose tissue may explain these discrepancies, they are more likely owing to confounding effects produced by race variances in skin color[34]. Race-related visceral adiposity differences may also be the reason for the different associations between obesity and vitamin D among different ethnic groups[30, 35]. Therefore, further investigation research is needed to observe the relation of serum vitamin D with obesity in childhood of various races.

Current researches suggest that the link between serum vitamin D concentrations and visceral fat in segregation by sex is generally complex. A study using bioelectrical impedance analysis showed that less visceral fat area reduced the incidence of vitamin D deficiency in premenopausal women and men, but the same result was not observed in postmenopausal women[36]. A Brazilian study of 190 pregnant women found no link between vitamin D and visceral fat on ultrasonography[37]. This study found that in sex-stratified subgroup analysis, the negative connection between blood vitamin D levels and VAT mass only exists in girls. Similar to our research, another study using C.T. observed an inverse connection between 25(O.H.)D and VFA in healthy young females aged 16–22 years[38]. The inconsistency of vitamin D-VAT association in these results may be explained by the lack of similarity in assay methods, individual growth and developmental stages among the different research.

There are some limitations to this study. For started, because this was a cross-sectional investigation, the causal relationship between serum vitamin D levels and VAT could not be established. Secondly, our research is conducted among teenagers, so it cannot be extended to other groups. However, our research has some strengths. The data come from a representative sample of multi-ethnic people, so it can be used as a general survey of American teenagers. In addition, to our knowledge, our study is the largest research to investigate the link between adolescent serum vitamin D levels and VAT, which increases the study's credibility.

To sum up, this study found that serum vitamin D levels were inversely linked with VAT. This relationship depends on race and gender, and our research found no negative link between girls and black. More prospective trials are necessary to further assess whether increasing serum vitamin D levels have a favorable effect on VAT in adolescents with vitamin D deficiency.

NHANES: National Health and Nutrition Examination Survey; VAT: visceral adipose tissue; CVD: cardiovascular disease; SAT: subcutaneous adipose tissue; DXA: dual-energy X-ray absorptiometry; BMI: body mass index.

Acknowledgments

We thank the colleagues of the National Health and Nutrition Examination Survey (NHANES) study for their effort in data collection.

Authors' contributions

L-YF and Z.X. contributed to the conception and design, the acquisition, analysis, interpretation of the data, the drafting of the article, or critical revision for important intellectual content. G-WL, L.Y., X-WM, W-XL, and Q-BW collected data. T.F. and C.Y. contributed to the conception and design, the reviewing of the article, or critical revision for important intellectual content. All authors approved the final version and agreed to be accountable for all aspects of the work.

Funding
This work was supported by Shanghai Municipal Administration of Traditional Chinese Medicine (Grant number: Z.Y. (2018-2020)-FWTX-8004). The funding source had no contribution to the study design, implementation, collection, and interpretation of data and report writing.

Availability of data and materials
Publicly available datasets were analyzed in this study. This data can be found here: https://wwwn.cdc.gov/nchs/nhanes/.

Ethics approval and consent to participate
The ethics review board of the National Center for Health Statistics approved all NHANES protocols, and written informed consent was obtained from all participants.

Consent for publication
Not applicable.

Competing interests
The authors declare that they have no competing interests.

Author details
¹Department of Rehabilitation, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200071, China.

²Department of Rehabilitation, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200071, China.

³Department of Endocrinology, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200071, China.

⁴Department of Endocrinology, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200071, China.

⁵Department of Endocrinology, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200071, China.

Blüher M. Obesity: global epidemiology and pathogenesis. Nat reviews Endocrinol. 2019;15(5):288–98.
Schetz M, De Jong A, Deane AM, Druml W, Hemelaar P, Pelosi P, Pickkers P, Reintam-Blaser A, Roberts J, Sakr Y, et al. Obesity in the critically ill: a narrative review. Intensive Care Med. 2019;45(6):757–69.
Piché M-E, Tchernof A, Després J-P. Obesity Phenotypes, Diabetes, and Cardiovascular Diseases. Circ Res. 2020;126(11):1477–500.
Tchernof A, Després J-P. Pathophysiology of human visceral obesity: an update. Physiol Rev. 2013;93(1):359–404.
Fox CS, Massaro JM, Hoffmann U, Pou KM, Maurovich-Horvat P, Liu C-Y, Vasan RS, Murabito JM, Meigs JB, Cupples LA, 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.
Holick MF. Vitamin D deficiency. N Engl J Med. 2007;357(3):266–81.
Wimalawansa SJ. Associations of vitamin D with insulin resistance, obesity, type 2 diabetes, and metabolic syndrome. J Steroid Biochem Mol Biol. 2018;175:177–89.
Peterlik M, Cross HS. Vitamin D and calcium deficits predispose for multiple chronic diseases. Eur J Clin Invest. 2005;35(5):290–304.
Ganji V, Sukik A, Alaayesh H, Rasoulinejad H, Shraim M. Serum vitamin D concentrations are inversely related to prevalence of metabolic syndrome in Qatari women. Biofactors. 2020;46(1):180–6.
Grandi NC, Breitling LP, Brenner H. Vitamin D and cardiovascular disease: systematic review and meta-analysis of prospective studies. Prev Med. 2010;51(3–4):228–33.
Pantovic A, Zec M, Zekovic M, Obrenovic R, Stankovic S, Glibetic M. Vitamin D Is Inversely Related to Obesity: Cross-Sectional Study in a Small Cohort of Serbian Adults. J Am Coll Nutr. 2019;38(5):405–14.
Song Q, Sergeev IN. Calcium and vitamin D in obesity. Nutr Res Rev. 2012;25(1):130–41.
Soares MJ, Chan S, Ping-Delfos W, Ghanbari MH. Calcium and vitamin D for obesity: a review of randomized controlled trials. European journal of clinical nutrition 2011, 65(9).
Cheng S, Massaro JM, Fox CS, Larson MG, Keyes MJ, McCabe EL, Robins SJ, O'Donnell CJ, Hoffmann U, Jacques PF, et al. Adiposity, cardiometabolic risk, and vitamin D status: the Framingham Heart Study. Diabetes. 2010;59(1):242–8.
Sulistyoningrum DC, Green TJ, Lear SA, Devlin AM. Ethnic-specific differences in vitamin D status is associated with adiposity. PLoS ONE. 2012;7(8):e43159.
Johnson CL, Dohrmann SM, Burt VL, Mohadjer LK. National health and nutrition examination survey: sample design, 2011–2014. Vital Health Stat 2 2014(162):1–33.
Zipf G, Chiappa M, Porter KS, Ostchega Y, Lewis BG, Dostal J. National health and nutrition examination survey: plan and operations, 1999–2010. Vital Health Stat 1 2013(56):1–37.
Borrud L, Chiappa MM, Burt VL, Gahche J, Zipf G, Johnson CL, Dohrmann SM. National Health and Nutrition Examination Survey: national youth fitness survey plan, operations, and analysis, 2012. Vital Health Stat 2 2014(163):1–24.
Erkal MZ, Wilde J, Bilgin Y, Akinci A, Demir E, Bodeker RH, Mann M, Bretzel RG, Stracke H, Holick MF. High prevalence of vitamin D deficiency, secondary hyperparathyroidism and generalized bone pain in Turkish immigrants in Germany: identification of risk factors. Osteoporos international: J established as result cooperation between Eur Foundation Osteoporos Natl Osteoporos Foundation USA. 2006;17(8):1133–40.
Rajakumar K, de las Heras J, Chen TC, Lee S, Holick MF, Arslanian SA. Vitamin D status, adiposity, and lipids in black American and Caucasian children. J Clin Endocrinol Metab. 2011;96(5):1560–7.
Lenders CM, Feldman HA, Von Scheven E, Merewood A, Sweeney C, Wilson DM, Lee PDK, Abrams SH, Gitelman SE, Wertz MS, et al. Relation of body fat indexes to vitamin D status and deficiency among obese adolescents. Am J Clin Nutr. 2009;90(3):459–67.
Wortsman J, Matsuoka LY, Chen TC, Lu Z, Holick MF. Decreased bioavailability of vitamin D in obesity. Am J Clin Nutr. 2000;72(3):690–3.
Compston JE, Vedi S, Ledger JE, Webb A, Gazet JC, Pilkington TR. Vitamin D status and bone histomorphometry in gross obesity. Am J Clin Nutr. 1981;34(11):2359–63.
McCarty MF, Thomas CA. PTH excess may promote weight gain by impeding catecholamine-induced lipolysis-implications for the impact of calcium, vitamin D, and alcohol on body weight. Med Hypotheses. 2003;61(5–6):535–42.
Kong J, Li YC. Molecular mechanism of 1,25-dihydroxyvitamin D3 inhibition of adipogenesis in 3T3-L1 cells. Am J Physiol Endocrinol metabolism. 2006;290(5):E916–24.
Bouchi R, Takeuchi T, Akihisa M, Ohara N, Nakano Y, Nishitani R, Murakami M, Fukuda T, Fujita M, Minami I, et al. High visceral fat with low subcutaneous fat accumulation as a determinant of atherosclerosis in patients with type 2 diabetes. Cardiovasc Diabetol. 2015;14:136.
Hoffmann U, Massaro JM, D'Agostino RB, Kathiresan S, Fox CS, O'Donnell CJ. Cardiovascular Event Prediction and Risk Reclassification by Coronary, Aortic, and Valvular Calcification in the Framingham Heart Study. J Am Heart Assoc 2016, 5(2).
Young KA, Engelman CD, Langefeld CD, Hairston KG, Haffner SM, Bryer-Ash M, Norris JM. Association of plasma vitamin D levels with adiposity in Hispanic and African Americans. J Clin Endocrinol Metab. 2009;94(9):3306–13.
Dong Y, Pollock N, Stallmann-Jorgensen IS, Gutin B, Lan L, Chen TC, Keeton D, Petty K, Holick MF, Zhu H. Low 25-hydroxyvitamin D levels in adolescents: race, season, adiposity, physical activity, and fitness. Pediatrics. 2010;125(6):1104–11.
Lee S, Kuk JL, Hannon TS, Arslanian SA. Race and gender differences in the relationships between anthropometrics and abdominal fat in youth. Obes (Silver Spring Md). 2008;16(5):1066–71.
Freedman DS, Wang J, Thornton JC, Mei Z, Pierson RN Jr, Dietz WH, Horlick M. Racial/ethnic differences in body fatness among children and adolescents. Obes (Silver Spring Md). 2008;16(5):1105–11.
Rush EC, Scragg R, Schaaf D, Juranovich G, Plank LD. Indices of fatness and relationships with age, ethnicity and lipids in New Zealand European, Māori and Pacific children. Eur J Clin Nutr. 2009;63(5):627–33.
Tybor DJ, Lichtenstein AH, Dallal GE, Daniels SR, Must A. Racial differences in central adiposity in a longitudinal cohort of black and white adolescent females. BMC Pediatr. 2010;10:2.
Looker AC. Body fat and vitamin D status in black versus white women. J Clin Endocrinol Metab. 2005;90(2):635–40.
Bacha F, Saad R, Gungor N, Janosky J, Arslanian SA. Obesity, regional fat distribution, and syndrome X in obese black versus white adolescents: race differential in diabetogenic and atherogenic risk factors. J Clin Endocrinol Metab. 2003;88(6):2534–40.
Zhang M, Li P, Zhu Y, Chang H, Wang X, Liu W, Zhang Y, Huang G. Higher visceral fat area increases the risk of vitamin D insufficiency and deficiency in Chinese adults. Nutr Metab (Lond). 2015;12:50.
Cisneiros R, Segatto J, Paixão E, Bacellar Í, Lima M, Pacheco Á, Alves JG, Bandeira F. Vitamin D deficiency and visceral adipose tissue in early pregnant women. BMC Pregnancy Childbirth. 2021;21(1):476.
Kremer R, Campbell PP, Reinhardt T, Gilsanz V. Vitamin D status and its relationship to body fat, final height, and peak bone mass in young women. J Clin Endocrinol Metab. 2009;94(1):67–73.

Table 1: Weighted characteristics of study population based on serum vitamin D levels.

Characteristic	Deficiency1272 (<50 nmol/L)	Insufficiency1425 (>=50, <75 nmol/L)	Sufficiency474 (>=75 nmol/L)	P value
Age, mean ± SD (years)	15.55 ± 2.24	15.28 ± 2.22	15.45 ± 2.22	0.0143
Gender (%)				<0.0001
Boys	47.47	58.08	49.62
Girls	52.53	41.92	50.38
Race (%)				<0.0001
Mexican American	25.59	14.71	4.00
Other Hispanic	10.12	8.43	2.83
Non-Hispanic White	21.67	58.41	85.28
Non-Hispanic Black	31.97	9.30	2.24
Other Race-Including Multi-Racial	10.65	9.15	5.65
Ratio of family income to poverty, mean ± SD	1.90 ± 1.46	2.56 ± 1.62	2.89 ± 1.53	<0.0001
Six month time period (%)				<0.0001
November 1 through April 30	59.22	48.06	26.83
May 1 through October 31	40.78	51.94	73.17
Sedentary activity, mean ± SD, (minutes)	513.61 ± 178.69	488.62 ± 159.21	465.02 ± 157.85	<0.0001
Waist circumference, mean ± SD, (cm)	85.82 ± 17.34	82.64 ± 15.38	79.16 ± 11.71	<0.0001
BMI, mean ± SD (kg/m²)	25.81 ± 7.33	24.11 ± 6.13	22.69 ± 4.66	<0.0001
Serum vitamin D, mean ± SD (nmol/L)	38.73 ± 8.57	61.86 ± 7.01	92.41 ± 17.63	<0.0001
Visceral adipose tissue mass (mg)	267.48 ± 166.11	244.06 ± 133.50	208.22 ± 108.58	<0.0001

Mean ± SD for continuous variables: P value was calculated by weighted linear regression model

% for categorical variables: P value was calculated by weighted chi-square test

Abbreviation: BMI, body mass index

Table 2: Association between serum vitamin D levels (nmol/L) and visceral adipose tissue mass (mg).

	Model 1 β (95% CI) P value	Model 2 β (95% CI) P value	Model 3 β (95% CI) P value
Serum vitamin D levels (nmol/L)	-1.23 (-1.44, -1.02) <0.0001	-1.63 (-1.86, -1.39) <0.0001	-0.38 (-0.53, -0.23) <0.0001
Serum vitamin D (quartile)
Deficiency	Reference	Reference	Reference
Insufficiency	-23.42 (-34.94, -11.90) <0.0001	-37.93 (-50.06, -25.81) <0.0001	-10.95 (-18.40, -3.51) 0.0040
Sufficiency	-59.26 (-72.50, -46.02) <0.0001	-78.22 (-92.95, -63.48) <0.0001	-18.05 (-27.25, -8.86) <0.0001
P trend	<0.001	<0.001	0.002
Stratified by race
Mexican American	-2.57 (-3.28, -1.86) <0.0001	-2.60 (-3.32, -1.88) <0.0001	-0.63 (-1.04, -0.21) 0.0033
Other Hispanic	-1.22 (-2.04, -0.41) 0.0035	-1.20 (-2.01, -0.38) 0.0042	-0.36 (-0.86, 0.13) 0.1519
Non-Hispanic White	-1.78 (-2.21, -1.35) <0.0001	-1.81 (-2.24, -1.38) <0.0001	-0.35 (-0.62, -0.08) 0.0103
Non-Hispanic Black	-0.86 (-1.36, -0.35) 0.0009	-0.95 (-1.45, -0.45) 0.0002	-0.04 (-0.40, 0.32) 0.8234
Other Race-Including Multi-Racial	-0.57 (-1.09, -0.04) 0.0339	-0.61 (-1.13, -0.09) 0.0219	-0.14 (-0.47, 0.19) 0.4145
Stratified by gender
Boys	-0.87 (-1.16, -0.58) <0.0001	-1.15 (-1.46, -0.84) <0.0001	-0.07 (-0.26, 0.12) 0.4415
Girls	-1.43 (-1.74, -1.12) <0.0001	-2.02 (-2.38, -1.66) <0.0001	-0.44 (-0.65, -0.22) <0.0001

Model 1 adjust for: None.

Model 2 adjust for: age, race and gender.

Model 3 adjust for: age, race, gender, sedentary activity, ratio of family income to poverty, six month time period, BMI, and waist circumference.

In the subgroup analysis stratified, the model is not adjusted for the stratification variable itself.

Associations between serum vitamin D levels and visceral adipose tissue among adolescents: a cross-sectional observational study in NHANES 2011-2015

Status:

Version 1

Abstract

Backgrounds:

Methods

Results

Conclusions

Figures

Background

Methods

Result

Discussion

Conclusions

Abbreviations

Declarations

References

Tables

Status:

Version 1