Comparison of respondents and nonrespondents in an osteoporosis study

We attempted to enroll an age-stratified random sample of Rochester, Minnesota women ≥ 30 years of age in a population-based prospective study of the determinants of bone loss. Using the resources of the Rochester Epidemiology Project, 541 women were contacted and 305 agreed to participate. Of 236 nonrespondents, 38 were ineligible and 198 refused to participate resulting in a 61% response rate for eligible subjects. We reviewed community medical records for respondents and nonrespondents (including ineligibles) to determine whether the two groups differed with regard to variables that might be important in osteoporosis research. There was little difference between respondents and nonrespondents for a history of cigarette smoking, hyperthyroidism, thyroidectomy, or age-related fractures. Respondents survived better, were less likely to be obese or have renal failure, and more likely to have had an oophorectomy and consume alcohol (P < 0.01). These data suggest that nonrespondents were less healthy than respondents.