The relationship between weight loss and all-cause mortality in older men and women with and without diabetes mellitus: the Rancho Bernardo study.

OBJECTIVES: To examine the relationship between measured weight change over an approximate 10-year time period on all-cause mortality over the following 12 years in 1,801 community-dwelling men and women (mean age 71 at the beginning of mortality follow-up) with and without diabetes mellitus.

DESIGN: A longitudinal cohort study.

SETTING: A geographically defined community in southern California.

PARTICIPANTS: One thousand eight hundred one older men and women with and without diabetes mellitus.

MEASUREMENTS: Weight, body mass index (BMI), blood pressure, and fasting plasma glucose were measured in 1972-74 (Visit 1) when participants were aged 40 to 79 and again in 1984-87 (Visit 2). Lifetime weight history and dieting for weight control were ascertained in 1985 using a mailed questionnaire. Vital status was determined for the next 12 years, from Visit 2 (1984-87) through 1996. The Cox proportional hazards model was used to assess the age- and multiply adjusted effect of weight change on mortality.

RESULTS: At Visit 1, diabetic men (n = 140) and women (n = 90) were more overweight than nondiabetic men (n = 633) and women (n = 938). Weight gain between Visits 1 and 2 was not a significant predictor of mortality in this cohort. Men and women losing 10 or more pounds between visits had higher age-adjusted death rates during the following 12 years than those with stable weight or weight gain. Weight loss was associated with an increased hazard ratio (HR) for all-cause mortality in nondiabetic men (HR = 1.38, 95% confidence interval (CI) = 1.06-1.80) and women (HR = 1.76, 95% CI = 1.33-2.34) and diabetic men (HR = 3.66, 95% CI = 2.15-6.24) and women (HR = 1.65, 95% CI = 0.70-3.87) after adjustment for age, smoking, and sedentary lifestyle. Significant associations persisted in analyses excluding cigarette smokers and those with depressed mood and low baseline BMI. After excluding those who died within 5 years of the weight loss, the increased HR was statistically significant in men and women with and without diabetes mellitus. Stratified analyses comparing those who reported dieting for weight control with those not dieting showed similar trends, with a higher mortality risk for weight loss in those who lost weight without dieting.

CONCLUSION: In this population of older individuals, weight loss predicted increased all-cause mortality risk not explained by covariates.