The risk of developing colorectal cancer increases with advancing age. More than 90% of cases occur in people aged 50 or older. Other risk factors include having:
Inflammatory bowel disease.
A personal or family history of colorectal cancer or colorectal polyps.
A genetic syndrome such as familial adenomatous polyposis (FAP) or hereditary non-polyposis colorectal cancer (Lynch syndrome).
Lifestyle factors that may contribute to increased risk of colorectal cancer include:
Lack of regular physical activity.
Low fruit and vegetable intake.
A low-fiber and high-fat diet.
Alcohol consumption.
References: http://www.cdc.gov/cancer/colorectal/basic_info/risk_factors.htm
Don't wait for symptoms to occur. Your doctor will tell you whether a simple at-home test or a colonoscopy is appropriate. Both are fully or partially covered by most medical insurance plans.