Colorectal cancer risk in relation to antidepressant medication use.

Laboratory studies suggest that antidepressants affect the risk of some cancers, including colorectal cancer. To investigate whether selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs) are associated with colorectal cancer risk, we conducted a case-control study among enrollees of an integrated healthcare delivery system in Washington State. Cases were first diagnosed with invasive colorectal cancer between 2000 and 2003; controls were randomly selected from Group Health enrollees and matched to cases on age, sex and length of enrollment before diagnosis/reference date. We used logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) for colorectal cancer in relation to use of any antidepressant, SSRIs only or TCAs only, among 649 cases and 656 controls. Use of any antidepressant was associated with a reduced risk of colorectal cancer (OR = 0.7, 95% CI = 0.5-0.9). Associations were similar for persons who used SSRIs exclusively (OR = 0.7, 95% CI = 0.4-1.1) and TCAs exclusively (OR = 0.7, 95% CI = 0.5-1.2); however, this reduction in risk appeared limited to persons without a prior cancer at another site. Our data support findings from previous epidemiologic and animal studies that suggest antidepressants may reduce the risk of colorectal cancer. Future studies with larger sample sizes should further examine individual drugs as well as dose, duration and recency of use.

Colorectal cancer risk in relation to use of acid suppressive medications.

PURPOSE: Acid suppressants are commonly prescribed medications. Laboratory studies suggest a mechanism by which they could increase colorectal cancer (CRC) risk. A few epidemiologic studies have investigated acid suppressant use and CRC risk; none has documented an overall association. We sought to investigate whether acid suppressants are associated with CRC risk. METHODS: We conducted a case-control study among members of an integrated healthcare delivery system in Washington State. Cases (N = 641) were diagnosed with CRC between 2000 and 2003; controls (N = 641) were randomly selected from enrollees and matched to cases on age, sex, and length of enrollment. We used conditional logistic regression to estimate the odds ratios (ORs) and 95% confidence intervals (CI) for CRC associated with the use of any acid suppressive medication, proton pump inhibitors (PPIs) only, histamine receptor antagonists (H2 blockers) only, or both PPIs and H2 blockers in relation to the use of neither PPIs nor H2 blockers. RESULTS: Use of PPIs exclusively was modestly associated with an increased risk of CRC, however this finding was consistent with chance and based on a small number of patients exposed (OR = 1.7; 95%CI = 0.8, 4.0). H2 blocker use alone was not related to CRC risk (OR = 0.8; 95%CI = 0.6, 1.1). CONCLUSIONS: PPI use may be modestly associated with CRC risk; further research should be conducted in populations with long-term PPI use.