Weight, physical activity, and smoking as determinants of insulinemia in adolescents

Background. It is known that insulinemia is the result of the interaction a mong several factors, such as weight, body fat pattern distribution, and ph ysical activity as well as ethnicity. There is little information regarding this question among Mexican adolescents, The association among fasting ins ulin levels, weight, fat distribution, physical activity, and cigarette smo king was studied in Mexican adolescents. Methods. Cross-sectional data were collected from 352 Mexican adolescents a ged 14-19 years (response rate 41.5%). Fasting insulin levels were measured by microparticle enzyme immunoassay; body mass index (BMI), waist-to-hip r atio (WHR), and waist circumference (WC) were determined using standardized techniques, while physical activity was determined by 7-day Stanford physi cal activity inventory. Cigarette smoking was defined as number of cigarett es/year. Results, Increased BMI and waist circumference, low physical activity, youn ger age, and non-smoking were associated with high insulin levels. Non-smok ers had higher fasting insulin levels compared to smokers (57.8 pmol +/- 1. 84 vs, 49.7 pmol/L +/- 2.8; p = 0.034). However, adjusted odds ratio (OR) b etween insulin and smoking status was not significant. Multivariate analysi s showed the following: insulin increased 1.06 pmol/L for each unit of chan ge in BMI; increased 1.02 pmol/L for each unit of change in waist circumfer ence; increased 1.16 pmol/L for non-smoking, and decreased 1.07 pmol/L for each 250 kcal/day of energy expenditure. Conclusions. Our results support the concept that Mexican adolescents who a re overweight have abdominal fat distribution and physical inactivity, and significant hyperinsulinemia. The relationship between smoking and lower in sulinemia found in this research warrants further study, (C) 2001 IMSS. Pub lished by Elsevier Science Inc.