Methods and Limitations

Methodology

The percentage of U.S. adults with diabetes who report at least one day in the past 30 days of poor mental health, poor physical health, poor mental or physical health, poor mental and physical health, and inability to do usual activities was determined by using data from the Behavioral Risk Factor Surveillance System (BRFSS). An ongoing, yearly, state-based telephone survey of the non-institutionalized adult population in each state, the BRFSS provides state-specific information on behavioral risk factors for disease and on preventive health practices.

Respondents were considered to have diabetes if they responded "yes" to the question, "Has a doctor ever told you that you have diabetes?" Women who indicated that they only had diabetes during pregnancy were not considered to have diabetes. Responses to the following questions were used to determine the prevalence of poor mental and physical health among persons with diabetes: “Now thinking about your mental health, which includes stress, depression, and problems with emotions, for how many days during the past 30 days was your mental health not good?”; “Now thinking about your physical health, which includes physical illness and injury, for how many days during the past 30 days was your physical health not good?”; “During the past 30 days, for about how many days did poor physical or mental health keep you from doing your usual activities, such as self-care, work, or recreation?”. We also combined information on mental health and physical health to estimate the percentage of adults with diabetes having either poor mental or physical health as well as having both poor mental and physical health.

Health status questions were in the core section for all the years except in 2002 when these questions were in optional module, which were used by 20 states. Therefore the 2002 estimates may not be national representative and were not presented for the national report. To improve the precision of the estimates, 3-year moving average were used to obtain estimates by state and only those states with at least two years data were presented. National estimates were based on single year data. Rates were age-adjusted to the 2000 U.S. standard population using age group of 18-44, 45-64, 65-74, and 75+ for national estimates and age group of 18-64 and 65+ for state estimates.

Limitations

Persons residing in nursing homes and in households without telephones are not included in this survey; therefore, these results cannot be generalized to those segments of the population. All data in the BRFSS are obtained by self-report and are subject to recall bias or may be underreported or overreported. Self-report of diabetes and self-report of sociodemographic characteristics are highly accurate (1, 2). Further investigation of the reliability and validity of self-reported mental and physical health is needed.

References

1. Bowlin SJ, Morrill BD, Nafziger AN, Lewis C, Pearson TA. Reliability and changes in validity of self-reported cardiovascular disease risk factors using dual response: the Behavioral Risk Factor Survey. J Clin Epidemiol 1996;49:511-7.
2. Stein AD, Courval JM, Lederman RI, Shea S. Reproducibility of responses to telephone interviews: demographic predictors of discordance in risk factor status. Am J Epidemiol 1996;141:1097-1106.