Stunting and thinness are major nutritional deficiencies and health problems in developing countries. In this study, the prevalence of thinness was 3 to 6 times the rate of stunting. This finding further highlights the view that malnutrition is still a major health problem affecting children and adolescents in Nigeria and other sub-Saharan African countries. Stunting is caused by a diet that is consistently low in quality and quantity, and it is a good sign of chronic undernutrition. Thinness, on the other hand, is a sign of chronic energy deficiency. Assessing stunting and thinness is important for several reasons. First, they are known to result from poor environmental conditions exacerbated by poor socioeconomic status. Hence, the extent of stunting and thinness is commonly used to determine the level of deprivation that commonly precedes developing nutritional policies and intervention strategies. Second, monitoring and evaluation of recovery from stunting in the form of catch-up growth in infancy or adolescence is an assessment of the effectiveness of the intervention programme. Third, the functional performance of adults is significantly associated with their extent of stunting at childhood [23], and women who were stunted earlier in life and remained stunted as adults, are more likely to have stunted children12. Stunting is also particularly detrimental to females because a woman’s stature has been reported to be directly proportional to the width of her pelvis [24]. A narrow pelvis can lead to protracted labour and often damages the newborn.
Despite the fact that undernutrition has decreased in many parts of the world, Africa remains a continent where children and adolescents suffer from nutritional inadequacies [16, 25]. The rates of severe (z-score <-3) and moderate (z-score <-2) stunting in the overall population were 4.4% and 14.3% respectively. The rates of severe and moderate stunting in boys (5.6% and 17.8%) and girls (3.2% and 10.9%) showed significant sexual dimorphism. The growth patterns in height of Nigerian children and adolescents are better than those reported in some African countries. The rates in Tanzania were 30% [26], in rural Mozambique, stunting rates of 24.2% for boys and 21.1% for girls have been reported [27]. A lower prevalence of stunting has been reported in other studies, 8.8% in Burkina Faso [28] and 7.2% in Addis Ababa [29]. The rate of stunting seen in this study is of great concern to children and adolescents, especially girls, whose stature has the potential to transcend one generation and its consequences for parturition. Even though nutritional interventions during the first 1000 days are the most important way to prevent short stature, there is evidence that interventions during adolescence offer another chance to break the cycle of undernutrition that can last for generations.
Agriculture is the mainstay of the Nasarawa economy, with maize, rice and yam being the most popular foods. An examination of patterns of foods available to a subsample of the population suggests that the majority of the subjects have access to carbohydrate rich foods, which may probably justify the level of chronic undernutrition observed in this paper. These food types predominantly provide the body with its energy needs and are often prepared and served with little or no protein (for body building and repair of muscles and bones), such as meat, fish, eggs or beans. Furthermore, intakes of certain vitamins are variable and may have been affected by seasonality and access to homegrown fruits and vegetables. As a result, their bodies' overall energy intake was not restricted, but their protein, micronutrient, and macronutrient intakes remained concerning. Other researchers have discovered a correlation between not getting enough nutrients and being short for age [30, 31].
Thinness was the most prevalent burden of undernutrition observed in this study. The prevalence of severe (z-score <-3) and moderate (z-score <-2) thinness in the combined population was 23.0% and 47.8% respectively. The rates of severe and moderate thinness were 27.5% and 52.4% in boys. In girls, the rates of severe and moderate thinness were 18.8% and 43.7%. This level of thinness in an urban setting is a serious public health concern considering its association with starvation. Despite differences in methodologies and/or criteria used for assessment of nutritional status, evidence from studies in other parts of Africa has shown high rates of thinness [31–33]. The high prevalence of thinness seen in this study is an indication of the remarkable condition of chronic protein energy deficiency among Nigerian children and adolescents. Socioeconomic factors such as family income, family size and parental educational status, may influence nutritional status. Children from families with a high socioeconomic status and higher parental education are more likely to have access to better nutrition than their peers from families with a lower socioeconomic status. The findings in this study further support the view that insecurity, inflation and ethnoreligious crises might have heightened food insecurity in Nigeria. Evidence from a subset of the subjects revealed that poverty and ignorance may have influenced the level of undernutrition seen in this study.
Our findings that girls have better nutritional status than boys are consistent with prior research in Sub-Saharan Africa [27, 34–37]. In the subjects in this study, the mean z-scores of height-for-age for all subjects, boys and girls, were − 0.68 1.37, -0.80 1.47, and − 0.57 1.26, respectively. The mean z-scores of BMI-for-age for the overall subjects, boys and girls, were respectively − 1.94, 1.32, -2.16 1.31, and − 1.75 1.31. The negative z-scores for anthropometric data are consistent with findings in other parts of Africa. The Z-scores for boys were significantly lower compared to girls, which suggests that boys are more susceptible to undernutrition than girls. Although it is hard to overstate the fact that obesity has remained a major public health concern worldwide, while developing countries suffer from double burden malnutrition (coexistence of under and overnutrition), that doesn’t seem to be the case with the subjects in this study. Evidence suggests that this disparity between boys and girls may be due to greater adaptation of girls to harmful environmental conditions than boys [38, 39], boys’ engagement in strenuous physical activities after school than girls; and gender bias in terms of increased attention on female children has resulted in better nutrition in girls than in boys. The sex difference in the pattern of growth may be due to intensive exercise (high energy expenditure) among boys rather than girls. For instance, it is common practice for boys of the age considered in this study to engage in hawking, skill acquisition, or support their parents on farms (especially during the rainy season) after school. Furthermore, differences in pubertal timing between boys and girls have also been reported as factors influencing growth and nutritional status [38].
We present smoothed reference percentile curves for height, weight and BMI of children and adolescents aged 5–18 years. There was no subnational or national prevalence of stunting and thinness of children and adolescents aged 5–18 years for comparison with the present study. However, the nutritional status of Nigerian children and adolescents as assessed from height-for-age and BMI-for-age reference curves indicates that undernutrition prevailed in these children and adolescents compared to the WHO (2007) definitions (Fig. 1). The 3rd and 50th growth curves of height-for-age in Nigerian children and adolescents of both sexes remain below the corresponding percentiles of WHO (2007) references. This is in concordance with previous findings in other sub-Saharan African countries [26, 34]. Although the growth curves of height-for-age of Nigerian children and adolescents remain below the 3rd and 50th percentiles of the WHO (2007) reference data, the 97th percentiles for Nigerian children were just above the WHO (2007) reference data from age 5–14 years, after which the trend reversed with WHO (2007) being above their Nigerian peers. It is observed that the linear growth of Nigerian children accelerates between the ages of 5–14 years in both sexes, then begins to falter. The gradual decline in height might indicate a decline in pubertal growth spurt. The decelerating growth pattern at adolescence observed in this study is similar to that earlier reported in the Nigerian population [40]. With the help of the LMS parameters that are sex- and age-specific to the nearest completed 6-months of age for a child or adolescent, z-scores can be calculated that match the new reference percentiles for a given traditional anthropometric measurement (x) (i.e., height, weight, or BMI) with the equation:
z-score = [(x \(÷\) M)L \(-\) 1] \(÷\) S \(\times\) L
In conclusion, to our knowledge, no study has been conducted in Lafia, Nasarawa State with a view to assessing the nutritional status and generating new reference percentile ranges for height, weight and BMI and LMS coefficients needed for estimation of z-score based on age- and sex. The present study reveals a high prevalence of undernutrition among children and adolescents in Lafia metropolis. The prevalence of thinness and stunting was higher in boys compared to girls. This study also showed that the height and BMI percentile curves of children and adolescents in Nigeria are below WHO (2007) reference data.