Sex differences in insulin sensitivity and insulin response with increasing age in black South African men and women.

Abstract

AIMS:

Black Africans are disproportionally affected by type 2 diabetes, but the pathophysiology is poorly understood. The study aimed to examine the effect of sex and age on insulin sensitivity and insulin response in black South African adults.

METHODS:

This cross-sectional study included a random sample of 179 men and 260 women aged 25-74years with normal glucose tolerance from 5 peri-urban townships in Cape Town, SA. Insulin sensitivity (insulin sensitivity index, ISI0,120) and response (insulinogenic index, IGI), and the disposition index (DI, ISI0,120×IGI), derived from an oral glucose tolerance test, were measured.

RESULTS:

Although men were older (median [interquartile range]: 39 [30-48] vs. 35 [29-44], P=0.021) and had significantly lower BMI than women (22.6 [20.0-25.3] vs. 31.0 [25.9-35.7] kg/m2, P=0.001), DI was not different (P=0.740), but ISI0,120 was higher (P=0.007) and IGI was lower (P=0.074) in men than women, adjusting for age and BMI. With increasing age, DI (β (95%CI): -24.4 (-36.3 to -12.5), P<0.001) and IGI (β (95%CI): -4.9 (-7.5 to -2.2), P<0.001) decreased similarly in both sexes, but ISI0,120 did not change (β (95%CI): 0.005 (-0.20 to 0.03), P=0.675).

CONCLUSION:

Black South African women with normal glucose tolerance have lower insulin sensitivity than their male counterparts, but increase their insulin response to maintain normoglycemia. With increasing age, insulin sensitivity remains unchanged, but the insulin response decreases at a similar rate in men and women.

• Authors: Julia H Goedecke, Cindy George, Katherine Veras, Nasheeta Peer, Carl Lombard, Hendriena Victor, Krisela Steyn, Naomi S Levitt
• Journal: Diabetes research and clinical practice (Diabetes Res Clin Pract) Vol. 122 Pg. 207-214 (Dec 2016) ISSN: 1872-8227 [Electronic] Ireland
• PMID: 27889690 (Publication Type: Journal Article)
• Copyright: Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Chemical References

• Blood Glucose
• Hypoglycemic Agents
• Insulin

Topics

• Adult
• Age Distribution
• Age Factors
• Aged
• Blood Glucose (drug effects, metabolism)
• Cross-Sectional Studies
• Diabetes Mellitus, Type 2 (blood, drug therapy, epidemiology)
• Female
• Glucose Tolerance Test
• Humans
• Hypoglycemic Agents (therapeutic use)
• Incidence
• Insulin (therapeutic use)
• Insulin Resistance
• Male
• Middle Aged
• Prevalence
• Sex Distribution
• South Africa (epidemiology)