Vitamin D status and its relationship with metabolic syndrome risk factors among adolescent girls in Boukan, Iran

Abstract

Objective: To investigate vitamin D status and its association with components of the metabolic syndrome (MetS) in adolescent girls attending high school in Boukan, Iran during winter 2012. Design: A cross-sectional study. Setting: High schools of Boukan city, Iran. Subjects: A sample of 216 girls aged 14-17 years was selected by multistage random sampling from four districts of Boukan. Weight, height, waist circumference, blood pressure, daily energy intake, physical activity and serum 25-hydroxyvitamin D (25(OH)D), fasting blood glucose, TAG and HDL-cholesterol levels of all participants were evaluated. Serum 25(OH)D level ,20 ng/ml was defined as vitamin D deficiency. Results: Mean serum 25(OH)D was 7?26 (SD 2?81) ng/ml and 96 % of the participants had vitamin D deficiency. According to age-modified definitions of the National Cholesterol Education Program Adult Treatment Panel III, MetS was diagnosed in 10?6 % of the participants. In multivariable regression analysis after adjustment for BMI, energy intake and physical activity level, serum 25(OH)D was inversely associated with fasting blood glucose (b 5 20?143, P 5 0?04). No significant relationship was found between serum 25(OH)D and other components of MetS. Conclusions: The high prevalence of vitamin D deficiency warrants national polices and interventions towards improving this major health problem among adolescent girls. Low 25(OH)D level was significantly associated with increased fasting blood glucose. Prospective studies are needed to determine the effects of vitamin D deficiency on the development of MetS and related metabolic diseases in adolescent girls. Keywords Vitamin D Prevalence Metabolic syndrome Adolescent girlsVitamin D deficiency is a major public health problem and an unrecognizable condition of epidemic proportions in both developed and developing countries, with widespread reports of 30-93 % prevalence in children and adults (1)(2)(3) . Determination of vitamin D status in different age groups in a community and in different climates of a country is necessary and has important implications for general health. Recent studies suggest that vitamin D deficiency is no longer just a problem of the older generations but also is an important health concern among younger generations (4) . Studies in the last two decades have shown a high prevalence of vitamin D deficiency in healthy adolescents in different countries (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15) . In Iran, Razzaghy-Azar and Shakiba and Moussavi et al. reported that 67 % of female children and adolescents in Tehran and 72?1 % of teenage girls in Isfahan had vitamin D deficiency, with higher rates of deficiency in girls than boys (16,17) . Vitamin D is known as the 'sunshine vitamin' because the mean exposure to sunlight should be sufficient for most people to produce their own vitamin D using UV light and cholesterol in the skin (18) . Whenever sun exposure is insufficient, dietary intake of this vitamin becomes a necessity. However, there are few dietary sources of vitamin D...

Physical Activity, Sedentary Behavior, Cardiorespiratory Fitness and Metabolic Syndrome in Adolescents: Systematic Review and Meta-Analysis of Observational Evidence

“…Taking into consideration all the studies included in the systematic review, 10 achieved scores ≥ 9 (high quality) [11,13–16,19,21–24], and nine studies scored 6–8 (moderate quality) [7–9,12,18,20,25–27]. Only two studies attained scores between 4–5 (low quality) [10,17]; and no study achieved a score ≤ 3 (very low quality).…”

“…The 17 observational studies included in the systematic review which associated outcomes involving physical activity and MetS (Table 1 [7,9–20,23–26]) were published between 2008 and 2016. Of these, seven studies were from Asia [9–12,14,19,20], four from South America [7,13,15,16], three from North America [24–26], two from Europe [17,23] and one from Africa [18].…”

“…Whenever available the most adjusted OR (adjusted statistically for different covariates) was taken directly from the publications [14,17,18,20,23,25]. However, when OR scores were not available in the studies included in the systematic review [9,12,15,19,22], absolute data were taken for the total quantity of volunteers and MetS events in each meta-analysis comparison category. For missing data, the authors of the selected studies [8,10,11,13,16,21,23–27] were contacted on at least three occasions by one of the reviewers (RGO).…”

“…For physical activity, studies [9,12,13,16,19,24,26] presenting data on moderate and high levels of practice separately, were brought together in a single group. In relation to the cut-off points for physical activity, the classifications used by each study were considered, which varied according to the measuring instrument used in their designs.…”

“…Another issue is the fact that the majority of studies [7,9,10–15,17,18,20,21,23–26] utilize self reported measures to evaluate physical activity and sedentary behavior, through questionnaires and recall records. Self reported measures can compromise the validity of the collected data, a fact which is amplified in young people due to the difficulty teenagers have to accurately remember the intensity, duration and frequency of physical activity [33].…”