Combined impact of five lifestyle factors and subsequent risk of cancer: the Japan Public Health Center Study.

Objective: To evaluate whether 5 combined healthy lifestyle factors (not smoking, moderate drinking, eating minimum salt-preserved foods, being physically active, and having appropriate body mass index) are associated with reduced risk of cancer.
Methods: Participants were enrolled in the Japan Public Health Center Study and responded to the 5-year follow-up questionnaire covering lifestyle factors in 1995-1999 at ages 45-74 years. During follow up through December 31, 2006, 3451 and 2125 cases of cancer were newly identified in men and women, respectively. For men and women, a factor-dependent risk reduction was observed for healthy lifestyles and cancer development. Compared to 0-1 healthy lifestyle factors, the adjusted RRs and 95% CIs for adherence to 2, 3, 4, and 5 healthy factors were 0.86 (0.78-0.95), 0.72 (0.65-0.80), 0.61 (0.54-0.69), and 0.57 (0.45-0.72), respectively, for men (P for trend<0.0001) and 0.86 (0.53-1.40), 0.73 (0.46-1.16), 0.68 (0.42-1.08), and 0.63 (0.39-1.01), respectively, for women (P for trend=0.0003). Risk was reduced 14% and 9% by each one healthy lifestyle for men and women, respectively. Risk reduction was more pronounced among elderly women.
Conclusion: These combined lifestyle factors have a considerable impact on preventing cancer.
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