Incidence rates were similarly estimated according to
categories of coffee intake based on 24 years of follow - up for the 5933 men whose intake was also determined 6 years later (1971 - 1974).
The ICRs were negative when considering smokers who had a coffee intake up to 3 cups / d, but they were positive for those who had a higher coffee intake, suggesting the
effect of coffee intake may be non-linear.
Main Outcome Measure Incident PD, by
amount of coffee intake (measured at study enrollment and 6 - year follow - up) and by total dietary caffeine intake (measured at enrollment).
Association of coffee intake with total and cause - specific mortality in a Japanese population: the Japan Public Health Center — based Prospective Study.
Prospective cohort studies were included if they reported relative risks (RRs) and corresponding 95 % confidence intervals (CIs) of various cancers with respect to
frequency of coffee intake.
For each study, the following information was extracted: first author's last name; year of publication; country of origin; follow - up period; number of subjects and cases; age at baseline; cancer sites; category amounts
of coffee intake; outcome assessment; relative risks or hazard ratios of cancer and corresponding 95 % CIs for every category of coffee intake; and covariates adjusted in the statistical analysis.