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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,
1.031.62) and 1.31 (95% CI, 1.011.70).
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, 1.061.26) and borderline
insignificant with frontal-plus-severe-vertex
baldness (OR, 1.14; 95% CI, 0.981.33).
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
Link...
Cancer Epidemiol Biomarkers
Relationship of early-onset baldness to prostate
cancer in African-American men
Link...
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