Coffee consumption was linked to different Parkinson’s risks depending on a participant’s genetics and sex, a study has found.
Drinking fewer than five cups a day was associated with a lower risk among people with the CYP1A2 AA genotype, particularly women.
By contrast, five or more cups a day was linked to a higher risk among people with AC or CC genotypes, particularly men.
The researchers wrote: “These findings underscore the complex interplay between genetics, sex, and coffee.
They added: “Our results emphasise the necessity of integrating both genetic and sex-based stratification into epidemiological models to elucidate context-dependent risk–benefit patterns, thereby supporting personalised prevention strategies and guiding future mechanistic research.”
Researchers analysed data from 435,551 people in the UK Biobank, including 3,319 who were diagnosed with Parkinson’s over a median follow-up of 15.7 years.
The study compared participants’ daily coffee intake with variations in CYP1A2, a gene that encodes an enzyme which helps the liver break down caffeine.
Around 52 per cent of participants had the AA genotype, while 40 per cent had the AC genotype and 8 per cent had the CC genotype.
When coffee consumption was not taken into account, researchers found no differences in Parkinson’s frequency between the three genetic groups.
Among people with the AA genotype, drinking fewer than five cups of coffee a day was associated with a 17 per cent lower risk of developing Parkinson’s.
The lowest estimated risk was at around two to three cups a day. Drinking five or more cups was not significantly associated with either a higher or lower risk in this group.
Among people with the AC genotype, five or more cups a day was associated with a 43 per cent higher risk of Parkinson’s.
For people with the CC genotype, the estimated risk was 84 per cent higher.
The researchers said the findings may reflect differences in how quickly people with different CYP1A2 variants process caffeine.
Differences also emerged when men and women were analysed separately.
Among women with the AA genotype, drinking fewer than five cups a day was associated with a 27 per cent lower risk of Parkinson’s. The association was not observed among men with the AA genotype.
Among men with the AC genotype, higher coffee consumption was linked to a 53 per cent higher risk.
For men with the CC genotype, the estimated risk was 137 per cent higher.
The observational study does not establish that coffee either causes or prevents Parkinson’s, and factors including smoking and alcohol consumption may have influenced the findings.
