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Influence of Increasing BMI on Insulin Sensitivity and Secretion in Normotolerant Men and Women of a Wide Age Span
Author(s) -
KautzkyWiller Alexandra,
Brazzale Alessandra R.,
Moro Ermanno,
Vrbíková Jana,
Bendlova Běla,
Sbrignadello Stefano,
Tura Andrea,
Pacini Giovanni
Publication year - 2012
Publication title -
obesity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.438
H-Index - 199
eISSN - 1930-739X
pISSN - 1930-7381
DOI - 10.1038/oby.2011.384
Subject(s) - medicine , endocrinology , overweight , quantitative insulin sensitivity check index , insulin sensitivity , insulin , population , diabetes mellitus , area under the curve , obesity , body mass index , insulin resistance , glucose tolerance test , environmental health
The impact of sex and age on glucose metabolism in the development of overweight/obesity is a matter of debate. We hypothesized that insulin sensitivity (IS) and β‐cell function (BF) in a normal white population will differ between males and females and aimed to evaluate the possible effects of BMI and age on metabolic parameters of both sexes. This study is a cross‐sectional analysis of the general community. IS was measured with quantitative insulin sensitivity check index (QUICKI) and oral glucose insulin sensitivity (OGIS) and BF with the insulinogenic index during 75‐g 2‐h oral glucose‐tolerance tests (OGTTs). We studied 611 females and 361 males with normal glycemia according to both fasting and 2‐h glucose (85 ± 0.3 mg/dl (means ± SE) in females and 89 ± 0.4 in males ( P < 0.0001), and 93 ± 1 in females and 89 ± 1 in males ( P = 0.005), respectively). Females were younger (37 ± 1 years) than males (40 ± 1, P < 0.0001), but no difference was found in mean BMI (BMI = 25.8 ± 0.2 kg/m 2 in both). Student's two‐sample t‐test was used for simple comparison between and within genders, multiple linear regressions to account for covariates. During the OGTT, females had lower glucose (area under the curve (AUC) 133 ± 1 mg/ml·2 h vs. 148 ± 2; P < 0.00001), while insulinemia was comparable (AUC 5.3 ± 0.1 mU/ml·2 h vs. 5.7 ± 0.2, P = 0.15). IS remained higher in females (473 ± 3 ml/min/m 2 vs. 454 ± 3, P < 0.0001) also after having accounted for age and BMI ( P = 0.015). No difference was observed in fasting insulin or BF. However, BF increased by 46% with BMI and when accounting for age and BMI, BF of females was significantly higher ( P < 0.0001). Because IS and BF are higher in females than in males, sex should be considered in metabolic studies and overweight/obese populations.