THE EPIDEMIOLOGY OF ADIPONECTIN DURING ADOLESCENCE: DEMOGRAPHIC, DEVELOPMENTAL, METABOLIC AND GENETIC ASSOCIATIONS
Obesity is increasingly prevalent among adolescents, and the health consequences of obesity are well-documented. Not all obese individuals experience metabolic dysfunction, possibly due to differences in adipocyte proteins, such as adiponectin. We know little about adiponectin in adolescence, when risks for metabolic disease are established. Therefore, we explored the relationships of demographic, developmental and metabolic traits with adiponectin levels, and associations between adiponectin gene variants, adiponectin levels and metabolic phenotypes in adolescents. We studied 1196 non-Hispanic white (NHW) and African-American (AA) adolescents in the Princeton City School District. In addition to existing data, including height, weight, waist circumference, puberty stage and blood lipids, insulin and glucose, we assayed plasma adiponectin and genotyped nine adiponectin gene variants. Insulin resistance was estimated using HOMA-IR. Adiponectin levels were higher in girls than boys, and higher in NHW than AA adolescents. Lean adolescents (BMI < 85%ile) had higher adiponectin levels than non-lean adolescents (BMI ? 85%ile). No sex differences were seen in pre-puberty, but boys’ levels were lower than girls’ in puberty and post-puberty. Adiponectin correlated negatively with body mass index (BMI) z-score, waist circumference, insulin, HOMA-IR, and triglycerides (TG), and positively with high-density lipoprotein (HDL) cholesterol. Correlations were significantly stronger among non-lean vs. lean adolescents for HOMA-IR, TG and HDL cholesterol, and interactions between adiponectin and BMI z-score were significant in models explaining HOMA-IR, HDL and TG. A haplotype in the adiponectin gene promoter (-11391, -10068 and -4521) was significantly associated with higher plasma adiponectin levels in NHW, but only marginally in AA. Surprisingly, this haplotype in NHW was also associated with lower HDL cholesterol and higher TG levels. In AA, haplotypes including variants from -10068 to +712 were independently associated with higher BMI z-score and TG. Sex and race differences in plasma adiponectin are established during puberty. Although adiponectin levels are lower among non-lean adolescents, the association with metabolic phenotypes increases with adiposity. Variants in the adiponectin gene influence adiponectin levels, adiposity and plasma lipid levels in a race-specific manner. Thus, adiponectin has a significant and changing role in adolescents’ metabolic phenotypes, and variants in the adiponectin gene contribute to these phenotypes.
School:University of Cincinnati
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:adiponectin adolescent genetic obesity
Date of Publication:01/01/2004