Impact of achievement and change in achievement of lifestyle recommendations in middle-age on risk of the most common potentially preventable cancers.

This study aimed to assess the association between achievement, and within-person change in achievement, of lifestyle recommendations in middle-age and incidence of the most common potentially preventable cancers. We used data from 44,572 participants from the Swedish Västerbotten Intervention Programme who had attended at least two health checks 9-11 years apart. We assessed the association between the mean number of healthy lifestyle recommendations achieved (lifestyle score), and change in lifestyle score between the health checks, and risk of one or more of the eight most common potentially preventable cancers using Cox regression. Participants were followed-up for 11.0 (SD 4.9) years. A higher mean lifestyle score was associated with a lower hazard of cancer in men (HR 0.81 (95%CI 0.74-0.90) per unit increase) and women (HR 0.90 (0.84-0.96)). There was no evidence of a linear association between change in lifestyle score and risk (HR 0.93 (0.85-1.03) and HR 1.004 (0.94-1.07) per unit change for men and women respectively). When comparing those with an increase in lifestyle score of ≥2 with those who improved less or declined in achievement the HR was 0.74 (0.54-1.00) and 1.02 (0.84-1.24) for men and women respectively. These findings support the inclusion of lifestyle recommendations in cancer prevention guidelines. They further suggest that interventions to change health behaviours in middle-age may reduce risk of the most common preventable cancers in men, but this association was not observed in women. Strategies to encourage healthy lifestyles earlier in the life course may be more effective.