Abstract and Introduction
Abstract
Objectives This study examined relations between elevated body mass index (BMI) and time to diagnosis with type 2 diabetes mellitus and its complications among older adults in the United States.
Methods Data came from the Medicare Current Beneficiary Survey, 1991–2010. A Cox proportional hazard model was used to assess relations between excess BMI at the first Medicare Current Beneficiary Survey interview and time to diabetes mellitus diagnosis, complications, and insulin dependence among Medicare beneficiaries, older than 65 years of age with no prior diabetes mellitus diagnosis, and who were not enrolled in Medicare Advantage (N = 14,657).
Results Among individuals diagnosed as having diabetes mellitus, elevated BMIs were associated with a progressively higher risk of complications from diabetes mellitus. For women with a BMI ≥40, the risk of insulin dependence (hazard ratio [HR] 3.57; 95% confidence interval [CI] 2.36–5.39) was twice that for women with 25 ≤ BMI < 27.5 (HR 1.77; 95% CI 1.33–2.33). A similar pattern was observed in risk of cardiovascular (25 ≤ BMI < 27.5: HR 1.34; 95% CI 1.15–1.54; BMI ≥40: HR 2.45; 95% CI 1.92–3.11), cerebrovascular (25 ≤ BMI < 27.5: HR 1.30; 95% CI 1.06–1.57; BMI ≥40: HR 2.00; 95% CI 1.42–2.81), renal (25 ≤ BMI < 27.5: HR 1.31; 95% CI 1.04–1.63; BMI ≥40: HR 2.23; 95% CI 1.54–3.22), and lower extremity complications (25 ≤ BMI < 27.5: HR 1.41; 95% CI 1.22–1.61; BMI ≥40: HR 2.95; 95% CI 2.35–3.69).
Conclusions Any increase in BMI above normal weight levels is associated with an increased risk of being diagnosed as having complications of diabetes mellitus. For men, the increased risk of these complications occurred at higher BMI levels than in women. Ocular complications occurred at higher BMI levels than other complication types in both men and women.
Introduction
Type 2 diabetes mellitus is a common disease whose prevalence is expected to double by the year 2030. The mean lifetime risk of developing type 2 diabetes mellitus for individuals born in the United States in 2000 was 38.5% for men and 32.8% for women. In 2006, the United States had a crude diabetes mellitus prevalence rate of 12.9% among individuals age ≥20, of whom approximately 40% were undiagnosed. The prevalence of diabetes mellitus peaked at ages 60 to 74. Among people aged 60 to 74, 29.9% had diabetes mellitus and another 36.85% were considered prediabetic, thus yielding a total diabetes mellitus and prediabetes prevalence rate of 66.7%. In 2009, an individual diagnosed as having type 2 diabetes mellitus faced a mean duration of disease of 14.9 years (men) and 17.0 years (women), and a reduction in life expectancy of 7.3 (men) and 9.5 (women) years.
The prevalence of excess body weight has increased dramatically in the United States in the past 50 years. In 2010, 69.2% of the US adult population had a body mass index (BMI) above normal levels. Among adults older than age 60, the prevalence of excess weight was even higher. Adult obesity is predicted to rise by 33% in the next 2 decades, with a prevalence of severe obesity rising by 130%. Combined with the aging of the baby boomer generation (individuals born between 1946 and 1964), these projections imply that there will be as many as 65 million more obese adults in 2030 than in 2010, 24 million of whom will be older than age 60.
Several published studies have reported a strong association between excess weight and an increased risk of developing various diseases, particularly type 2 diabetes mellitus. To illustrate, women who are overweight, in obese classes I and II (30 ≤ BMI < 39.99) and class III (BMI ≥40) face up to a 7.6%, 20.1%, and 38.8%, respectively, greater risk of developing type 2 diabetes mellitus in comparison with women with a normal BMI. Moreover, individuals diagnosed as having type 2 diabetes mellitus are at risk of developing a range of severe complications that lead to a significant reduction in their quality of life. For example, the risk of acute myocardial infarction (AMI) for individuals diagnosed as having type 2 diabetes mellitus is as high as that for individuals not diagnosed as having diabetes mellitus who previously have had an AMI. Furthermore, individuals with diabetes mellitus are 17 times more likely to have an amputation as a result of peripheral vascular disease and are at an increased risk of developing nephropathy, retinopathy, and coronary heart disease, among other adverse health outcomes.