Coronary heart disease incidence and mortality, and all-cause mortality among diabetic and non-diabetic people according to their smoking behavior in Finland.
BACKGROUND
As type 2 diabetes (T2D) patients have a high risk for coronary heart disease (CHD) and all-cause mortality and smoking is a major single risk factor for total and CHD mortality, it is important to understand the impact of smoking to the outcome events in comparison to people without T2D. Studies of excess risk of CHD incidence and mortality, and all-cause mortality in T2D patients related to smoking are controversial. We aimed to assess the risk of CHD incidence and mortality, and all-cause mortality in a large Finnish population cohort consisting of people with and without T2Daccording to smoking status.


METHODS
Prospective follow-up of 28 712 men and 30 700 women aged 25-64 years living in eastern and south-western Finland. The data on mortality were obtained from the nationwide death register using the unique national personal identification number. Follow-up information regarding CHD was based on the Finnish Hospital Discharge Register for non-fatal outcomes. The Cox proportional hazards models were used to estimate the association between diabetes and smoking subgroups and the risk for total and CHD mortality.


RESULTS
T2D patients who were smoking had higher all-cause mortality in both men (HR 3.76; 95% CI 2.95-4.78) and women (HR 4.51; 95% CI 2.91-7.00) than non-smoking diabetic men (HR 2.03; 95% CI 1.51-2.74) and women (HR 2.11; 95% CI 1.71-2.59). The CHD mortality risk for smoking men with T2D was higher (HR 6.15; 95% CI 4.22-8.96) than in non-smoking diabetic men (HR 2.62; 95% CI 1.60-4.29). Similar results were found in women revealing corresponding HR for CHD mortality of 6.92 (95% CI 2.79-17.19) for smoking, T2D women and 4.06 (95% CI 2.83-5.82) for non-smoking T2D women, respectively. Even though the risk of CHD incidence in T2D patients who had stopped smoking was statistically significantly higher than in their non-smoking non-diabetic counterparts, their CHD incidence was lower than in smoking T2D patients (HR in men 3.00; HR in women 2.80).


CONCLUSIONS
It is important to address tobacco consumption in T2D patients, especially during primary health care contacts in order to reduce their high risk of CHD and all-cause mortality.
Department of Medical and Population Health Sciences Research, Herberth Wertheim College of Medicine, Florida International University, 11200 SW 8th Street, AHC2, Miami, FL 33199 USA.
Noël C
NC
Barengo
Department of Neurosciences and Preventive Medicine, Danube-University Krems, Krems, Austria.
Yvonne
Y
Teuschl
Department of Health, National Institute for Health and Welfare, Helsinki, Finland.
Vladislav
V
Moltchanov
Department of Health, National Institute for Health and Welfare, Helsinki, Finland.|Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland.|Hospital District of North Karelia, Joensuu, Finland.
Tiina
T
Laatikainen
Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland.
Pekka
P
Jousilahti
Department of Neurosciences and Preventive Medicine, Danube-University Krems, Krems, Austria.|Department of Health, National Institute for Health and Welfare, Helsinki, Finland.|Dasman Diabetes Institute, Dasman, Kuwait.|Diabetes Research Group, King Abdulaziz University, Jeddah, Saudi Arabia.
Jaakko
J
Tuomilehto
Coronary heart disease; Diabetes mellitus; Mortality; Smoking