-Original-

The Effect of Insulin Resistance Improvement Due to Lifestyle Intervention on Overweight Perimenopausal Japanese Women: A Preliminary Study

Hiromitsu Chihara¹, Rieko Kawase¹, Yasuo Otsubo², Yoshie Hiraizumi¹ and Toshiyuki Takeshita¹

¹Department of Female Reproductive and Developmental Medicine, Graduate School of Medicine, Nippon Medical School
²Department of Obstetrics and Gynecology, Omiya Chuo Sogo Hospital

Objective: We hypothesized that body composition and biomarkers of menopausal obesity would be affected by administration of a nutrition and exercise regimen. To test this hypothesis, an interventional study was performed in which perimenopausal subjects increased their daily level of physical activity and decreased their daily caloric intake for a period of 12 weeks.
Method: Nine patients with a chief complaint of obesity and menopausal disorders were enrolled in this study. We prescribed that the subjects engage in the daily physical activity of walking more than 10,000 steps, which is equivalent to 150 to 400 kcal per day, and reduce their daily nutritional intake by 200 kcal. Daily physical activity was measured with a computerized accelerometer, and nutrition intake was measured using food frequency questionnaires. Body composition was measured via biophysical impedance analysis. Biochemical examinations were performed before and after the study. As an assessment of glucose tolerance, homeostasis model assessment-insulin resistance (HOMA-IR) values were measured.
Results: There were no significant changes in weight, body mass index, or body composition after 12 weeks. However, daily physical activity related to energy consumption was slightly but not significantly increased. Six of the nine subjects (66.7%) had abnormal baseline HOMA-IR values (mean 7.0 ± 2.6; normal upper limit = 1.5) and demonstrated decreases in HOMA-IR values, with an average of 5.2 ± 2.3 (P <0.05), after 12 weeks of study.
Conclusion: Our mild intervention on daily physical activity and nutrition changed HOMA-IR values, an assessment of impaired glucose tolerance. These results suggest that longitudinal mild intervention on daily physical activity and nutrition could change insulin sensitivity even without weight reduction.

J Nippon Med Sch 2008; 75: 15-22

Keywords
menopause, obesity, metabolic syndrome, physical activity, body composition

Correspondence to
Hiromitsu Chihara, Department of Obstetrics and Gynecology, Nippon Medical School Chiba Hokusoh Hospital, 1715 Kamakari, Inba-mura, Inba-gun, Chiba 270-1613, Japan
naru@nms.ac.jp

Received, January 9, 2007
Accepted, October 17, 2007