Body fat and lipid profile of monozygotic twins discordant for insulin resistance

Abstract

The study investigated alterations in body fat and metabolic profile of adolescent monozygotic twins, resulting from discordance for insulin resistance, adjusted for physical activity, physical fitness and heredity. Thirty-eight pairs of monozygotic twins were assessed for anthropometric measurements to estimate body fat. Physical fitness was estimated with treadmill test and use of ergospirometer. Daily physical activity was estimated from the daily count of steps measured by a pedometer during 3 days. Fasting blood samples were used to determine blood glucose, insulin, lipid parameters. The Homa-IR and HOMA-? indexes were calculated. Twins with measures higher than 2.5 were considered insulin resistant. When both brothers were below or above cutoffs, the pair was allocated to the concordant group. When one brother was insulin resistant and the other was not, the pair was allocated in the discordant group. Twins were compared using paired test. In the discordant group, it was observed that insulin-resistant twins had higher birth weight values, bodyweight, BMI, waist circumference, body fat percentage, body fat (sum of skinfolds), Homa-? index and lower HDL compared to their corresponding pair. Insulin-resistant twins showed higher values in anthropometry and body composition, as well as in the glycemia and insulin index and lower HDL. These events may have been unchained by metabolic alterations possibly originating from gestational stage, however, modulated by body composition.