Refereed journal article or data article (A1)
Abdominal adiposity and cardiometabolic risk factors in children and adolescents: a Mendelian randomization analysis
List of Authors: Viitasalo A, Schnurr TM, Pitkänen N, Hollensted M, Nielsen TRH, Pahkala K, Atalay M, Lind MV, Heikkinen S, Frithioff-Bøjsøe C, Fonvig CE, Grarup N, Kähönen M, Carrasquilla GD, Larnkjaer A, Pedersen O, Michaelsen KF, Lakka TA, Holm JC, Lehtimäki T, Raitakari O, Hansen T, Kilpeläinen TO
Publication year: 2019
Journal: American Journal of Clinical Nutrition
Volume number: 110
Issue number: 5
Start page: 1079
End page: 1087
Number of pages: 9
ISSN: 0002-9165
DOI: http://dx.doi.org/10.1093/ajcn/nqz187
BACKGROUND:
Mendelian randomization studies in adults
suggest that abdominal adiposity is causally associated with increased
risk of type 2 diabetes and coronary artery disease in adults, but its
causal effect on cardiometabolic risk in children remains unclear.
We
aimed to study the causal relation of abdominal adiposity with
cardiometabolic risk factors in children by applying Mendelian
randomization.
We constructed a genetic risk
score (GRS) using variants previously associated with waist-to-hip ratio
adjusted for BMI (WHRadjBMI) and examined its associations with
cardiometabolic factors by linear regression and Mendelian randomization
in a meta-analysis of 6 cohorts, including 9895 European children and
adolescents aged 3-17 y.
WHRadjBMI GRS was
associated with higher WHRadjBMI (β = 0.021 SD/allele; 95% CI: 0.016,
0.026 SD/allele; P = 3 × 10-15) and with unfavorable concentrations of
blood lipids (higher LDL cholesterol: β = 0.006 SD/allele; 95% CI:
0.001, 0.011 SD/allele; P = 0.025; lower HDL cholesterol: β = -0.007
SD/allele; 95% CI: -0.012, -0.002 SD/allele; P = 0.009; higher
triglycerides: β = 0.007 SD/allele; 95% CI: 0.002, 0.012 SD/allele;
P = 0.006). No differences were detected between prepubertal and
pubertal/postpubertal children. The WHRadjBMI GRS had a stronger
association with fasting insulin in children and adolescents with
overweight/obesity (β = 0.016 SD/allele; 95% CI: 0.001, 0.032 SD/allele;
P = 0.037) than in those with normal weight (β = -0.002 SD/allele; 95%
CI: -0.010, 0.006 SD/allele; P = 0.605) (P for difference = 0.034). In a
2-stage least-squares regression analysis, each genetically
instrumented 1-SD increase in WHRadjBMI increased circulating
triglycerides by 0.17 mmol/L (0.35 SD, P = 0.040), suggesting that the
relation between abdominal adiposity and circulating triglycerides may
be causal.
Abdominal adiposity may have a
causal, unfavorable effect on plasma triglycerides and potentially other
cardiometabolic risk factors starting in childhood. The results
highlight the importance of early weight management through healthy
dietary habits and physically active lifestyle among children with a
tendency for abdominal adiposity.
