OBJECTIVE: To compare longitudinal changes in weight, body fat, and ratio of central to peripheral fat mass among first-time depot-medroxyprogesterone acetate ( DMPA) users to women using no hormonal contraception, and to evaluate user characteristics associated with that change. DESIGN: Prospective longitudinal study. SUBJECTS: Healthy women, aged 18-35 y, using DMPA for contraception (n=178) and women using no hormonal contraception (n=145). MEASUREMENTS: Weight, body fat, and the central distribution of fat, measured at 3-month intervals for 30 months, by electronic scale and dual-energy X-ray absorptiometry ( DEXA). The ratio of central to peripheral distribution of body fat was computed by dividing the body fat in the conventional DEXA trunk region of interest (ROI) by the ROI's that encompass the arms, hips and legs. RESULTS: Women using DMPA had a significantly greater increase in all measures of fatness than women using no hormonal method of contraception (P < 0.03). The observed weight of DMPA users increased from a mean of 69.4 kg (s.d. = 16.9) at baseline to 75.5 kg (s.d. = 25.0) at 30 months; an increase of 6.1 kg (8.8.%). Fat mass increased from a mean of 25.3 kg (s.d. = 12.6 kg) at baseline to 31.4 kg (s.d. = 17.8); an increase of 6.1 kg (23.6%) in DMPA users. The ratio of central to peripheral fat mass in DMPA users changed from 0.95 (s.d. = 0.155) at baseline to 1.01(s.d. = 0.198) at 30 months. In contrast, weight, fat mass and the ratio of central to peripheral fat mass of control participants remained virtually unchanged over the same time period. Women with higher baseline physical activity levels had a smaller increase in body fat (P = 0.003) and the fat ratio (P = 0.03), but not weight ( P = 0.48). No other user characteristics including, smoking, past oral contraceptive use or previous pregnancies predicted change in level of fatness. CONCLUSIONS: This study has demonstrated a change in body composition toward greater fatness and toward a central redistribution of fat among DMPA users as compared to controls and provides important information to be used when counseling women regarding contraceptive methods. Given the potential long-term implication of these changes, further study is recommended to determine whether the gains in fatness are reversed following DMPA discontinuation and to examine the role of progestins in the development and maintenance of obesity.
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