The high prevalence of obesity in Michigan primary care practices. An UPRNet study. Upper Peninsula Research Network

Obesity is a risk factor for several chronic diseases and some cancers. We suspected that patients in our primary care practices were, on the average, heavier than state and national norms.

Rates of overweight patients in primary care practices were compared with rates from the Michigan Behavioral Risk Factor Survey (MBRFS) of 1993 and the National Health and Nutrition Evaluation Survey (NHANES) III Phase I (1988-91), the most recent state and national surveys for which summarized data were available. The 19 family practice offices of the rural Upper Peninsula Research Network (UPRNet) and two urban clinics in the Lansing area participated. We measured heights and weights of 5267 consecutive patients 18 years of age and older who visited one of the offices or clinics during the study period in 1996.

Fifty-three percent of the primary care patients were overweight, and 28.5% were severely overweight. The age-adjusted rates were 51.0% and 27.5%, respectively. These rates are much higher than rates reported from the MBRFS (29.1% for overweight), and NHANES III Phase I (33% overweight, 14% severely overweight). The age-adjusted prevalence of overweight and severely overweight was higher in the rural than the urban sample: 52.5% vs 47.2% for overweight and 33.7% vs 25.6% for severely overweight, respectively.

Compared with data from the Michigan Behavioral Risk Factor Survey of 1993 and the National Health and Nutrition Evaluation Survey III Phase I, a much larger proportion of patients visiting our primary care practices are overweight and severely overweight. The prevalence of obesity in primary care practices may be much higher than rates estimated from population-based surveys.