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Male pattern baldness may increase risk of colon cancer (2016-02-15)

A new first-of-its-kind study has found a link between certain types of male pattern baldness and increased risk of colorectal polyps. Such polyps can be precursors to colorectal cancer.

Male pattern baldness, the most common type of hair loss in men, is positively associated with androgens as well as IGF-1 and insulin, all of which are implicated in pathogenesis of colorectal neoplasia. Therefore, it is biologically plausible that male pattern baldness, as a marker of underlying aberration in the regulation of the aforementioned hormones, may be associated with colorectal neoplasia.

In men with frontal baldness (a receding hairline) and with frontal-plus-mild-vertex baldness (receding hairline plus slight baldness on the crown of the head), researchers found approximately 30% increased risk of colon cancer relative to men with no baldness, said NaNa Keum, research fellow in the Department of Nutrition at Harvard T.H. Chan School of Public Health and lead author of the study, in a January 14, 2016 interview in MedicalResearch.com.

While the relationship between male pattern baldness and prostate cancer risk has been widely examined, to our knowledge, this study represents the first to report a potential relationship between male pattern baldness and the risk of colorectal neoplasia. Thus, our findings should be confirmed in other studies before making definite clinical recommendations.

In a recent prospective cohort study conducted among participants in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, it was only frontal-plus-moderate-vertex baldness at age 45 years that was associated with an increased risk of aggressive prostate cancer (Zhou et al, 2015).

“It may be prudent for males with frontal-only-baldness or frontal-plus-mild-vertex-baldness at age 45 years, although their elevated risk is modest, to consult physicians about colonoscopy screening guidelines,” Keum said.

For the study, published January 12, 2016 in the British Journal of Cancer, researchers followed about 33,000 men over an average of nearly 16 years who were participants in the Health Professionals Follow-Up Study.

From 1992 through 2010, researchers prospectively followed participants in the Health Professionals Follow-Up Study.
Hair pattern at age 45 years was assessed at baseline with five image categories (no baldness, frontal-only baldness, frontal-plus-mild-vertex baldness, frontal-plus-moderate-vertex baldness, and frontal-plus-severe-vertex baldness).
Cancer analysis included 32,782 men and used Cox proportional hazards models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).
Restricted to men who underwent at least one endoscopy over the study period, adenoma analysis included 29,770 men and used logistic regressions for clustered data to estimate odds ratios (ORs) and 95% CIs.

Over the mean follow-up of 15.6 years, 710 cases of colorectal cancer (478 for colon, 152 for rectum, and 80 unknown site) developed. Significantly increased risks associated with frontal-only baldness and frontal-plus-mild-vertex baldness relative to no baldness were observed for colon cancer with respective HR being 1.29 (95% CI, 1.03–1.62) and 1.31 (95% CI, 1.01–1.70).

Over the 19-year study period, 3526 cases of colorectal adenoma were detected. Evidence for an increased risk of colorectal adenoma relative to no baldness was significant with frontal-only baldness (OR, 1.16; 95% CI, 1.06–1.26) and borderline insignificant with frontal-plus-severe-vertex baldness (OR, 1.14; 95% CI, 0.98–1.33).

Subtypes of male pattern baldness at age 45 years were positively associated with colorectal neoplasia. Future studies are warranted to confirm our results and to determine the predictive value of male pattern baldness to identify those at high risk for colorectal neoplasia.

For more information
British Journal of Cancer
Male pattern baldness and risk of colorectal neoplasia

Cancer Epidemiol Biomarkers
Relationship of early-onset baldness to prostate cancer in African-American men