Relation between body mass index and lung cancer risk in men and women never and former smokers

The authors assessed body mass index (BMI), measured as Quetelet's index (weight in kilograms divided by the square of height in meters), in relation to lung cancer risk in never and former smokers by using data from a population-based, individually matched, case-control study conducted in New York State from 1982 to 1985. To be included in the study, subjects must never have smoked more than 100 cigarettes in their lifetime (never smokers) or not have smoked more than 100 cigarettes during the last 10 years (former smokers). Data on height and weight were complete for 412 of 439 case-control pairs. A positive relation was found between BMI and lung cancer risk for both never smokers (188 case-control pairs) and former smokers (224 pairs). When subjects were combined, those in the eighth (highest) octile (BMI > 30.84) had more than twice the odds of being cases compared with those in the lowest octile (BMI < or =21.26, 95 percent confidence interval: 1.2, 4.4). These study results are consistent with those from studies of BMI and other cancer sites but differ from lung cancer results usually found in predominantly smoking populations.