Excess concordance of cancer incidence and lifestyles in married couples (Japan): survival analysis of paired rate data.
OBJECTIVE
A population-based cohort study was conducted to examine concordance of cancer incidence and lifestyle in married couples.


METHODS
Cancer incidence from 1 September 1986 to 30 June 2000 was followed for a baseline cohort of 2601 community-living married couples aged 40-84 years who were cancer-free and had completed an epidemiologic questionnaire in 1986 in Saitama, Japan. We computed age-adjusted cross-ratios: spouse-with/spouse-without rate ratios as a measure of association for paired rate data, using a bivariate survival analysis method.


RESULTS
Concordance of lifestyles for couples was high for dietary habits, and low for smoking and alcohol habits. During the 14 year follow-up, 464 cancer cases occurred (husbands only: 279, wives only: 119, both: 33 couples). Wives whose husbands developed cancer were at an increased risk of developing cancer themselves, compared with those whose husbands had not had cancer (CR: 1.70, 95% CI: 1.12-2.58). Mean age at diagnosis was 68.2 years for husbands and 66.0 years for wives. And correlation of cancer incidence was further seen among couples who shared habits of smoking and/or drinking.


CONCLUSIONS
Our data suggest that shared lifestyles including smoking and drinking habits are associated with an excess concordance of cancer incidence among married couples.
Izumi
Shizue
S
Department of Statistics RERF 5-2 Hijiyama Park Minami-ku Hiroshima 732-0815 Japan. izumi@ rerf.or.jp
Imai
Kazue
K
Nakachi
Kei
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000428:Alcohol Drinking / Q000009:adverse effects*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007564:Japan / Q000208:ethnology; D008019:Life Style; D008297:Male; D008393:Marriage; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D012907:Smoking / Q000009:adverse effects*