Dietary practices in households as risk factors for stomach cancer: a familial study in Poland.
In the framework of a nationwide case-control study of risk factors for stomach cancer, a household survey was conducted on those food habits at the family level which were considered relevant for stomach cancer. The practices of 741 case and 741 control households were compared and relative risks calculated by the unconditional maximum likelihood method. For each household, the person responsible for cooking completed the survey. Respondents to the household survey were 35% of the cases and 40% of the controls of the case-control study and otherwise other household members. Case households relied more frequently on their own gardens as a major source of vegetables and fruit, and they cooked their vegetables more often than control households. The vegetable and fruit consumption during the summer period per family member was significantly less in case households compared to control households. The difference in per capita vegetable and fruit consumption between case and control households persisted, but was considerably less pronounced when the consumption of the index person (case or control) was subtracted from the household consumption. The consumption of mainly wholemeal bread showed a relative risk (RR) of 0.18 (95% CI 0.07-0.44) compared with mainly white bread consumption, whereas frequent frying and stewing of meat was associated with an increased risk compared to boiling of meat (RR = 2.06, 95% CI 1.48-2.87). No association with risk was found for long-term refrigerator use or other storage modalities.(ABSTRACT TRUNCATED AT 250 WORDS)