Low serum 25-hydroxyvitamin D levels are associated with obesity and atherogenesis in adolescent boysRunning title: Low serum 25(OH)D and obesity and atherogenic risk in adolescents

Introduction The incidence rate of vitamin D deficiency is increasing throughout the world. We measured the incidence rate of vitamin D deficiency and fibroblast growth factor 23 (FGF23) levels in 12-to 13-year-old adolescents in Japan. Materials and methods A total of 492 adolescents (247 boys and 245 girls) from Japanese community enrolled in this study. 25 hydroxyvitamin D (25(OH)D) was measured with radioimmunoassay. In the subjects with low 25(OH)D levels (≦ 20 ng/ ml), intact parathyroid hormone (iPTH), calcium (Ca), phosphorus (P), albumin (Alb), alkaline phosphatase (ALP) and FGF23 were measured. Results 25(OH)D levels were significantly lower in girls (20.9 ± 3.1 ng/ml) than in boys (22.2 ± 3.3 ng/ml) (p < 0.0001). Fifty-five boys (22.3%) and 83 (33.9%) girls showed vitamin D deficiency (< 20 ng/ml). One-hundred eighty-six (75.3%) boys and 162 (66.1%) girls showed vitamin D insufficiency (≧ 20 ng/ml, < 30 ng/ml). In the subjects whose 25(OH)D levels were ≦ 20 ng/ml, the levels of iPTH, Ca, P, Alb, ALP and FGF23 were 22.3 ± 9.0 pg/ml, 9.5 ± 0.4 mg/dl, 4.7 ± 0.6 mg/dl, 4.6 ± 0.3 g/dl, 920.8 ± 339.3 U/l and 42.6 ± 26.0 pg/ml, respectively. There was a significant negative association between serum 25(OH)D levels and iPTH [r = − 0.290 (p < 0.0001)]. There was no significant association between serum 25(OH) D levels and FGF23. Conclusion We show that 28% of Japanese 12-to 13-year-old early adolescents suffer from vitamin D deficiency. Findings from this study indicate that vitamin D deficiency requires close oversight in public health during adolescence to ensure proper bone health.

Objectives Adiposity rebound (AR) refers to an increase in body mass index (BMI) after a nadir. Early AR, in which AR occurs earlier than five years old, is a risk factor for future obesity and metabolic syndrome, but has not been widely studied in very-low-birth-weight infants (VLBWIs). Methods The subjects were VLBWIs born in Dokkyo Medical University NICU from January 2008 to December 2010. Height and weight measured at birth and at intervals until seven years old were obtained from medical records. The lowest BMI after one year of age was used for the age of AR. The subjects were divided into those with early and normal AR (<5 and ≥5 years old). BMI percentile at age seven years was compared using the interquartile range (IQR). Changes in BMI were evaluated by repeated measures analysis of variance (ANOVA). Results There were 38 early AR cases and 62 normal AR cases, giving a prevalence of early AR similar to that in infants with normal birth weight. BMI percentile at age seven years was significantly higher in early AR cases than in normal AR cases (44.6 [IQR: 21.0–79.2] vs. 14.4 [IQR: 3.8–40.8] kg/m2). Changes in BMI were also significantly higher in early AR cases (p=0.024 by ANOVA). Conclusions Early AR in VLBWIs is a predictor of future obesity.

Purpose: If children show inadequate infant weight gain, their growth velocity will also decrease, especially £3 years of age. We hypothesized that such children may not only lead to being underweight but also short stature during childhood, and this trend will follow them through adolescence. Methods: A total of 271 children were enrolled. The Pearson correlation coefficients were calculated to determine the relationships of the increment of weight gain £3 years, from birth to 1.6 years and from 1.6 years to 3 years of age, with height and weight at 3, 7 years and pubertal age, respectively. Results: The Pearson correlation coefficients between weight gain each of from birth to 1.6 years and from 1.6 years to 3 years of age and weight at pubertal age were 0.34 and 0.37 in boys and 0.47 and 0.48 in girls, and height at pubertal age were 0.34 and 0.24 in boys and 0.65 and 0.40 in girls, respectively. Conclusions: Insufficient weight gain in children £3 years, especially £1.6 years is not only associated being underweight, but also short stature at 3 and 7 years and at the onset of puberty and it is also suspected that adult height and weight may be affected.

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