I wish they wouldn't even bother reporting these meta-analysis projects. They aren't scientifically rigorous. And it makes them feel good about providing some new knowledge. But why don't they do the hard work and challenge their intellect to find out how to save brain cells from the neuronal cascade of death in the first week, saving hundreds of millions to billions of neurons?
Moderate coffee intake protects against stroke
A new meta-analysis, including the most contemporary studies that have
examined coffee consumption and risk of cardiovascular events in a
general population, has found that moderate intake may help protect
against ischemic stroke [1].
Presenting the results at the recent European Society of Hypertension (ESH) European Meeting on Hypertension 2012, Dr Lanfranco D'Elia (Federico II University of Naples, Italy) told heartwire:
"The first message is that coffee intake is not associated with a
higher risk of stroke," which he says is reassuring. "Second, the
analysis showed that low to moderate intake—one to three cups of coffee
per day—was associated with lower risk of stroke in the general
population, across a wide range of countries, including some in Europe,
the US, and Japan."
However D'Elia stressed that these results
apply to the general population only and that findings with regard to
coffee intake and risk in those with cardiovascular disease have been
conflicting. Nevertheless, he believes that "one coffee a day is not
dangerous for people with heart disease."
Protective effect independent of most identifiable confounders
D'Elia and colleagues performed a
meta-analysis of the available prospective studies, including those that
estimated baseline coffee consumption and risk of stroke in the general
population, from 1966 to 2011. However, the majority of studies
included were performed in the late 2000s, including a recent Swedish study and one from the Netherlands.
One to three cups of coffee per day was associated with lower risk of stroke in the general population.
For this analysis, coffee consumption was
stratified into moderate (one to three cups/day), high (three to six),
and very high (six or more) and compared with the reference category
(zero to one). For each study, the values of relative risk (RR) and
their confidence interval were extracted and then combined using a
random effect model. Eight general-population studies were included in
the analysis, for a total of 11 cohorts (484 757 participants, 7272
stroke events, follow-up two to 24 years).
In the pooled analysis, habitual moderate
coffee consumption was associated with decreased risk of stroke (RR
0.86, 95% CI 0.75-0.98; p<0.02).
Stroke risk in the high-consumption category
showed a trend in the same direction, toward a reduction (RR 0.87, 95%
CI 0.70-1.08; p=0.02), which reached statistical significance upon
sensitivity analysis with the exclusion of a single outlier study (RR
0.81, 95% CI 0.70-0.95; p=0.01).
Habitual very high coffee consumption was not associated with any effect on stroke risk (RR 1.05, p=0.71).
D'Elia said that unlike low to moderate coffee
intake, both "high" and "very high" consumption showed a significant
heterogeneity between studies.
Statistical analysis did not find any
significant sources of heterogeneity (length of follow-up, publication
year, gender, countries, etc) that affected the relationship between
coffee intake and stroke risk, but he noted, "We cannot exclude the
potential limitations of the analysis around the standardization of
coffee preparation or different types of coffee.
"The results of this meta-analysis, which
included prospective studies of samples of the general population,
indicate that coffee consumption is not associated with a higher risk of
stroke and that actually habitual moderate consumption may exert a
protective effect independently from most identifiable confounders," he
concluded.
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