Coffee Consumption Is Positively Associated with Longer Leukocyte Telomere Length in the Nurses' Health Study.
Level 4 - case-series / case-control
Cross-sectional observational study nested within a cohort
PubMed 27281805 · doi:10.3945/jn.116.230490
What was done
Researchers evaluated the cross-sectional association between coffee and caffeine consumption and relative leukocyte telomere length among 4,780 women from the Nurses' Health Study. Dietary intake was assessed using validated food-frequency questionnaires, and relative telomere length was measured from peripheral blood leukocytes using quantitative real-time PCR. Multivariable unconditional logistic regression (dichotomizing telomere length at the median) and linear regression models were used to evaluate associations and trends after adjusting for potential confounders.
What was found
Higher total coffee consumption was positively associated with longer telomeres after multivariable adjustment. Compared to non-coffee drinkers, the multivariable odds ratios for having telomere length above the median were 1.29 (95% CI: 0.99 to 1.68) for 2 to <3 cups/day and 1.36 (95% CI: 1.04 to 1.78) for ≥3 cups/day (P-trend = 0.02). Total dietary caffeine intake was initially associated with telomere length (P-trend = 0.02), but the association was attenuated and no longer statistically significant after adjusting for total coffee intake (P-trend = 0.37).
Why it matters
These findings suggest that coffee consumption may be linked to cellular biomarkers of biological aging, potentially mediated by non-caffeine constituents such as antioxidants rather than caffeine itself.
Limits
The study is cross-sectional, preventing causal conclusions. Dietary intake was self-reported via food-frequency questionnaires. The study population was restricted exclusively to female nurses, limiting generalizability to men and other demographic groups. Telomere length was measured at a single point in time.
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