A number of studies have examined the association between smoking and incidence of glucose abnormalities, and have suggested that smoking could be independently associated with glucose intolerance, impaired fasting glucose and type 2 diabetes, which could make smoking a modifiable risk factor for type 2 diabetes. However, it appears the quality and clinical features of these studies have not been fully assessed regarding this possible association.
Carole Willi, M.D., of the University of Lausanne, Switzerland, and colleagues conducted a systematic review and meta-analysis of studies describing the association between active smoking and the incidence of diabetes or other glucose metabolism irregularities. A search of databases yielded 25 studies, which were published between 1992 and 2006. The number of participants per study ranged from 630 to 709,827, for a total of 1.2 million participants. A total of 45,844 new cases of diabetes were reported during a study follow-up period ranging from 5 to 30 years.
Analysis of the data indicated that active smokers have a 44 percent increased risk of developing type 2 diabetes compared with non-smokers. Further analyses suggested a dose-response relationship between smoking and diabetes, with the association stronger for heavy smokers (20 or more cigarettes/day; 61 percent increased risk) compared with lighter smokers (29 percent increased risk). The association also was weaker for former smokers (23 percent increased risk) than it was for active smokers.
Recommendations for type 2 diabetes prevention should incorporate smoking avoidance accompanied by lifestyle modification. Although a frequent concern of smoking cessation is subsequent weight gain, moderately increasing exercise can largely minimize the approximately [4.4 lbs.] weight gain associated with stopping smoking, indicating that the public health issues of smoking, exercise, and obesity are inextricably intertwined. Major population prevention of type 2 diabetes is achievable via avoidance of smoking and modification of lifestyle factors through a combination of healthy weight control, regular physical activity, moderate alcohol intake, and proper diet.