Insulin-dependent diabetes mellitus mortality. The risk of cigarette smoking.

The relation between cigarette smoking and mortality was examined prospectively in a population of adult insulin-dependent diabetes mellitus (IDDM) patients. In 1981, information on smoking history and other health and lifestyle factors was obtained by questionnaire from 93% of the 723 patients included in the Children's Hospital of Pittsburgh IDDM registry who were diagnosed between 1950 and 1964. Vital status as of January 1, 1988 was ascertained for 98% of the 548 patients who participated in the baseline survey and were alive as of January 1, 1982. Fifty-four cases died during the 6-year follow-up (32 male, 22 female). Proportional hazards analysis revealed that heavy smoking was a significant independent predictor of all-cause mortality among females but not males. The excess mortality in female diabetics was explained primarily by a marked excess risk of coronary heart disease mortality in smokers. These data strongly suggest that cigarette smoking, especially among diabetic females, should be avoided in order to improve longevity.