title: Allelic variations in the vitamin D receptor gene, insulin secretion and parents' heights are independently associated with height in obese children and adolescents.
abstract: Polymorphisms in the VDR gene were reported to be associated with variations in intrauterine and postnatal growth and with adult height, but also with other traits that are strongly correlated such as the BMI, insulin sensitivity, insulin secretion and hyperglycemia. Here, we assessed the impact of VDR polymorphisms on body height and its interactions with obesity- and glucose tolerance-related traits in obese children and adolescents. We studied 173 prepubertal (Tanner's stage 1) and 146 pubertal (Tanner's stages 2-5) obese children who were referred for a weight-loss program. Three single nucleotide polymorphisms were genotyped: rs1544410 (BsmI), rs7975232 (ApaI) and rs731236 (TaqI). BsmI and TaqI genotypes were significantly associated with height in pubertal children, but the associations did not reach statistical significance in prepubertal children. In stepwise regression analyses, the lean body mass, insulin secretion, BsmI or TaqI genotypes and the father's and the mother's height were independently and positively associated with height in pubertal children. These covariables accounted for 46% of the trait variance. The height of homozygous carriers of the minor allele of BsmI was 0.65 z-scores (4cm) higher than the height of homozygous carriers of the major allele (P=.0006). Haplotype analyses confirmed the associations of the minor alleles of BsmI and TaqI with increased height. In conclusion, VDR genotypes were significantly associated with height in pubertal obese children. The associations were independent from the effects of confounding traits, such as the body fat mass, insulin secretion, insulin sensitivity and glucose tolerance.
authors.affiliation: Laboratory of Human Nutrition and Metabolic Disease (LIM-25), Hospital de Clínicas da Faculdade de Medicina da Universidade de São Paulo, Avenida Doutor Arnaldo 455, Room 4305, CEP 01246-903, SP São Paulo, Brazil.
authors.forename: Daniela A F
authors.initials: DA
authors.lastname: Ferrarezi
authors.forename: Naïma
authors.initials: N
authors.lastname: Bellili-Muñoz
authors.forename: Christiane
authors.initials: C
authors.lastname: Nicolau
authors.forename: Nadir
authors.initials: N
authors.lastname: Cheurfa
authors.forename: Isabel C
authors.initials: IC
authors.lastname: Guazzelli
authors.forename: Eliana
authors.initials: E
authors.lastname: Frazzatto
authors.forename: Gilberto
authors.initials: G
authors.lastname: Velho
authors.forename: Sandra M
authors.initials: SM
authors.lastname: Villares
mesh_terms: D000293:Adolescent; D000483:Alleles; D001827:Body Height; D002648:Child; D005260:Female; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D008297:Male; D009765:Obesity / Q000235:genetics* / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D018167:Receptors, Calcitriol / Q000235:genetics*; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood
chemical_list: D007328:Insulin; D018167:Receptors, Calcitriol; D014807:Vitamin D; C104450:25-hydroxyvitamin D