Eichholzer M; Stahelin HB; Gey KF
Inverse correlation between essential antioxidants in plasma and subsequent
risk to develop cancer, ischemic heart disease and stroke respectively:
12-year follow-up of the Prospective Basel Study.
There is accumulating evidence that free radicals
may contribute to various diseases such as cancer or cardiovascular disease.
Possible health hazards can to some extent be prevented by the body's
multilevel defense system against free radicals, which comprises, besides
others, antioxidant vitamins. The 12-year mortality follow-up of 2,974
participants of the Basal Study allowed to test the hypothesis that low
antioxidant vitamin plasma concentrations (vitamin A, C, E and carotene)
were associated with increased death from cancer of various sites and
death from atherosclerosis such as ischemic heart disease and stroke,
respectively. For the analysis 204 cancer cases, 132 fatalities from ischemic
heart disease (IHD) and 31 deaths from cerebral vascular disease were
available. Cancer mortality. Overall mortality from cancer was associated
with low mean plasma levels of carotene adjusted for cholesterol (p less
than 0.01) and of vitamin C (p less than 0.01). Bronchus and stomach cancers
were associated with a low mean plasma carotene level (p less than 0.01).
Subjects with subsequent stomach cancer had also lower mean vitamin C
and lipid-adjusted vitamin A levels than survivors (p less than 0.05).
Calculating the relative risk with exclusion of mortality during the first
two years of follow-up, low plasma carotene was associated with an increased
risk for bronchus cancer (RR 1.8, p less than 0.05), and the small number
of stomach cancer cases (RR 2.95, p less than 0.05) low plasma levels
of carotene and vitamin A with all cancer types (RR 2.47, p less than
0.01), and low plasma retinol in older subjects (greater than 60 years)
with lung cancer (RR 2.17, p less than 0.05). Studies in other cohorts
with a poor vitamin E status revealed an increased risk of subsequent
cancer at low vitamin E levels as well. It is concluded that low plasma
levels of all major essential antioxidants are associated with an increased
risk of subsequent cancer mortality. Cardio-vascular mortality. Plasma
carotene concentration below quartile 1 was associated with an increased
risk for IHD (RR 1.53, p = 0.02). The same was true for low levels of
both carotene and vitamin C (RR = 1.96, p = 0.022). The risk of
cerebrovascular death was elevated in subjects with low carotene in the
presence of low vitamin C plasma concentration (RR 4.17, p less than 0.01).
These data confirm and extend recent findings on an inverse correlation
of beta-carotene and vitamin C respectively to CVD.