Impacts of family history and lifestyle habits on colorectal cancer risk: a case-control study in Qatar.

BACKGROUND: Associations between family history of colorectal cancer (CRC) in first degree relatives and risk of developing cancer have been well defined, but interactions with environmental, lifestyle and dietary factors are much less clear. AIM: The aim of this study was to evaluate family history, lifestyle and dietary factors associated with developing colorectal cancer in an Arab population. DESIGN: This matched case-control study was conducted from August 2008 to February 2009 in Al-Amal Hospital and Primary Health Care Centers in Qatar. SUBJECTS AND METHODS: The study covered 146 colorectal cancer patients from Al-Amal hospital and 282 healthy subjects matched by age and gender as controls from primary health care centers. The questionnaire included socio-demographic information, type of consanguinity, medical history, lifestyle habits, and dietary intake. Of the selected 185 colorectal cancer cases, 146 (78.9%) agreed to participate in the study, whereas from the 350 selected controls, 282 (80.6%) gave consent. RESULTS: The mean age of cases was 54.1±12.4 and of controls 53.1±13.1. Among the life style factors, being overweight and obese (60.2%; 30.1% p=0.006), having a smoking habit (26.7%, p=0.025), and consuming bakery items (78.8% p<0.001) and soft drinks (28.7% p<0.02), were positively associated with CRC. The majority of the studied cases and controls were consuming fresh fruits (87.7% vs 85.5%), fresh vegetables (95.2% vs 95%) and green salad (91.1% vs 89.4%) regularly. Family history of CRC (41.8%) was significantly higher in colorectal patients than in controls (29.1%) (p<0.01). Parental consanguinity was observed more frequently in colorectal cancer patients (35.6%). Multivariate stepwise logistic regression analysis showed that smoking, BMI, family history, consuming bakery and soft drinks were significant predictors of development of colorectal cancer. CONCLUSION: The present study revealed family history and parental consanguinity to be strongly associated with the development of colorectal cancer. Age, gender, a sedentary lifestyle, and being overweight were also positively linked with CRC risk