Higher Coffee Intake May Be Linked To Lower Prostate Cancer Risk

DRINKING several cups of coffee every day may be linked to a
lower risk of developing prostate cancer, suggests a pooled data
analysis of the available evidence, published in the online journal
BMJ Open.

Each additional daily cup of the brew was associated with a
reduction in relative risk of nearly 1%, the findings indicate.

Prostate cancer is the second most common cancer, and the sixth
leading cause of cancer death in men. Nearly three out of four
cases occur in the developed world, and since the 1970s, new cases
of the disease have risen sharply in Asian countries, including
Japan, Singapore, and China.

Coffee consumption has been linked to a lower relative risk of
liver, bowel, and breast cancers, but as yet, there is no
conclusive evidence for its potential role in prostate cancer risk
reduction.

In a bid to advance understanding of the issue, the researchers
trawled research databases for relevant cohort studies published up
to September 2020.

They pooled the data from 16:15 reported on the risk of prostate
cancer associated with the highest, compared with the lowest,
coffee consumption; 13 reported on the risk associated with an
additional daily cup. The highest level of consumption ranged from
2 to 9 or more cups a day; the lowest level ranged from none to
fewer than 2 cups a day.

The included studies were carried out in North America (7),
Europe (7) and Japan (2). They included more than 1 million men
(1,081, 586) of whom 57,732 developed prostate cancer.

Compared with the lowest category of coffee consumption, the
highest category was associated with a reduction in prostate cancer
risk of 9%. And each additional daily cup was associated with a
reduction in risk of 1%.

Further refining the analysis to localised and advanced prostate
cancer showed that compared with the lowest intake, the highest
intake was associated with a 7% lower risk of localised prostate
cancer, and a 12%-16% lower risk for advanced and fatal prostate
cancer, respectively.

The researchers acknowledge that because of the observational
design of the included cohort studies, unmeasured or uncontrolled
factors in the original studies may have skewed the pooled risk
estimate.

The amount of coffee drunk may also have been misclassified as
it depended on recall. And the type of coffee and brewing methods
varied among the studies. The design and methods of the included
studies also varied, so caution in interpreting the findings is
warranted, they say.

Nevertheless, there are plausible biological explanations for
their findings, they highlight.

Coffee improves glucose metabolism, has anti-inflammatory and
antioxidant effects, and affects sex hormone levels, all of which
may influence the initiation, development and progression of
prostate cancer, they point out.

And they conclude: “This study suggests that increased coffee
consumption may be associated with a reduced risk of prostate
cancer. Further research is still warranted to explore the
underlying mechanisms and active compounds in coffee.

“If the association is further proved to be a causal effect, men
might be encouraged to increase their coffee consumption to
potentially decrease the risk of prostate cancer.”

DRINKING several cups of coffee every day may be linked to a
lower risk of developing prostate cancer, suggests a pooled data
analysis of the available evidence, published in the online journal
BMJ Open.

Each additional daily cup of the brew was associated with a
reduction in relative risk of nearly 1%, the findings indicate.

Prostate cancer is the second most common cancer, and the sixth
leading cause of cancer death in men. Nearly three out of four
cases occur in the developed world, and since the 1970s, new cases
of the disease have risen sharply in Asian countries, including
Japan, Singapore, and China.

Coffee consumption has been linked to a lower relative risk of
liver, bowel, and breast cancers, but as yet, there is no
conclusive evidence for its potential role in prostate cancer risk
reduction.

In a bid to advance understanding of the issue, the researchers
trawled research databases for relevant cohort studies published up
to September 2020.

They pooled the data from 16:15 reported on the risk of prostate
cancer associated with the highest, compared with the lowest,
coffee consumption; 13 reported on the risk associated with an
additional daily cup. The highest level of consumption ranged from
2 to 9 or more cups a day; the lowest level ranged from none to
fewer than 2 cups a day.

The included studies were carried out in North America (7),
Europe (7) and Japan (2). They included more than 1 million men
(1,081, 586) of whom 57,732 developed prostate cancer.

Compared with the lowest category of coffee consumption, the
highest category was associated with a reduction in prostate cancer
risk of 9%. And each additional daily cup was associated with a
reduction in risk of 1%.

Further refining the analysis to localised and advanced prostate
cancer showed that compared with the lowest intake, the highest
intake was associated with a 7% lower risk of localised prostate
cancer, and a 12%-16% lower risk for advanced and fatal prostate
cancer, respectively.

The researchers acknowledge that because of the observational
design of the included cohort studies, unmeasured or uncontrolled
factors in the original studies may have skewed the pooled risk
estimate.

The amount of coffee drunk may also have been misclassified as
it depended on recall. And the type of coffee and brewing methods
varied among the studies. The design and methods of the included
studies also varied, so caution in interpreting the findings is
warranted, they say.

Nevertheless, there are plausible biological explanations for
their findings, they highlight.

Coffee improves glucose metabolism, has anti-inflammatory and
antioxidant effects, and affects sex hormone levels, all of which
may influence the initiation, development and progression of
prostate cancer, they point out.

And they conclude: “This study suggests that increased coffee
consumption may be associated with a reduced risk of prostate
cancer. Further research is still warranted to explore the
underlying mechanisms and active compounds in coffee.

“If the association is further proved to be a causal effect, men
might be encouraged to increase their coffee consumption to
potentially decrease the risk of prostate cancer.”