The harms of smoking and benefits of smoking cessation in women compared with men with type 2 diabetes: an observational analysis of the ADVANCE (Action in Diabetes and Vascular Disease: Preterax and Diamicron modified release Controlled Evaluation) trial

Abstract

Objectives: In general populations, the adverse effects of smoking on coronary risk have been demonstrated to be greater in women than in men; whether this is true for individuals with diabetes is unclear.

Design: Cohort study.

Setting: 20 countries worldwide participating in the ADVANCE (Action in Diabetes and Vascular Disease: Preterax and Diamicron modified release Controlled Evaluation) trial.

Participants: 11,140 patients with type 2 diabetes aged ≥ 55 years and in cardiovascular risk at the time of randomisation.

Primary and secondary outcome measures: Major cardiovascular events (death from cardiovascular disease, non-fatal stroke or non-fatal myocardial infarction (MI)), all cardiovascular events (major cardiovascular event or peripheral arterial disease or transient ischaemic attack), and all-cause mortality. Secondary outcome measures were major coronary events (fatal and non-fatal MI), major cerebrovascular events (fatal and non-fatal stroke), nephropathy (new or worsening renal disease), and all cancer.

Results: At baseline, 6466 (56% women) participants were never-smokers, 1550 (28% women) were daily smokers and 3124 (21% women) were former smokers. Median follow-up time was 5 years. In Cox regression models after multiple adjustments, compared with never smoking, daily smoking was associated with increased risk of all primary and secondary outcomes with the exception of major cerebrovascular disease. Only for major coronary events was there any evidence of a stronger effect in women than in men (ratio of the adjusted HRs women:men; 1.64 (0.83 to 3.26) p=0.08). For all other outcomes considered, the hazards of smoking were similar in men and women. Quitting smoking was associated with a 30% reduction in all-cause mortality (p=0.001) in both sexes.

Conclusions: In individuals with diabetes, the effects of smoking on all major forms of cardiovascular disease are equally as hazardous in women and men with the possible exception of major coronary events where there was some evidence of a greater hazard in women.

Trial registration number: NCT00145925.

Keywords: EPIDEMIOLOGY; PUBLIC HEALTH.

Figure 1

HR and 95% CIs for daily smoking versus never smoking. The total number of individuals is 8016. Cox models adjusted for age, sex, body mass index, randomised treatment groups, glycated haemoglobin, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, creatinine clearance, systolic blood pressure, heart rate, duration of diabetes, history of cardiovascular disease, any blood pressure medication, any lipid-lowering medication, use of acetyl salicylic acid or thienopyridines, exercise times per week, alcohol use and level of education.

Figure 2

Ratio of the HRs (women:men) for daily smoking versus never smoking. *Total number of women is 4075 and men is 3941. Cox model adjustments are as in figure 1.

Figure 3

HR and 95% CIs for former versus daily smoking. The total number of individuals is 4674. Cox model adjustments are as in figure 1.

Figure 4

Ratio of the HRs (women:men) for former versus daily smoking. *Total number of women is 1092 and men is 3582. Cox model adjustments are as in figure 1.