The deleterious effects of smoking have been established, but recent data published in JAMA indicate smoking cessation was associated with a lower risk for coronary heart disease among postmenopausal women with or without diabetes.
According to Juhua Luo, PhD, of the Indiana University School of Public Health, and colleagues, weight gained after smoking cessation weakened the association, especially in women with diabetes who gained 5 kg or more. However, due to the small number of cases, power was limited in that particular subgroup of women.
They used data from the Women’s Health Initiative (WHI) to categorize patients into four groups: never smokers (n=54,801), former smokers (n=42,912), current smokers (n=4,787) and newly quit (n=1,891). According to data, 3,381 out of 104,391 women included in the follow-up developed coronary heart disease (CHD) during a mean duration of 8.8 years.
Further, the incidence rates of CHD per 1,000 person-years were 3.3 in never smokers, 3.7 in former smokers, 7.6 in current smokers, and 5.3 those who had recently quit.
Cox proportional hazards regression model was used to estimate hazard ratios (HRs) for risk for CHD as it related to smoking status stratified by diabetes status and weight gain from baseline to 3 years (<5 kg, 5 kg to 10 kg and ≥10 kg), with and without additional adjustments, they wrote.
Of those without diabetes (n=98,053), those who recently quit had an adjusted HR for CHD of 0.74 (95% CI, 0.57-0.95), compared with current smokers. The adjusted HR for former smokers was 0.39 (95% CI, 0.34-0.45).
Of the 6,338 women with diabetes, those who had recently quit demonstrated a lower risk for developing CHD (HR=0.36; 95% CI, 0.17-0.78). This was also the case for former smokers (HR=0.41; 95% CI, 0.29-0.59), compared with current smokers, researchers wrote.
The researchers also made adjustments for weight changes. According to data, the link between smoking status and risk for CHD among women who gained less than 5 kg was similar to results in patients with and without diabetes.
Moreover, women without diabetes who gained 5 kg to <10 kg or ≥10 kg, who were categorized as former smokers, demonstrated a lower risk for CHD compared with current smokers. The researchers also reported no statistically significant risk for CHD among women with diabetes who gained 5 kg to <10 kg who recently quit or were former smokers, compared with current smokers. The number of women with diabetes and weight changes of ≥10 kg was too small for modeling, they wrote.
The researchers concluded that the study was limited to only postmenopausal women and did not take into consideration subsequent changes in smoking, weight, or status of diabetes after 3 years.
Disclosure: The researchers report no relevant financial disclosures.