Risk factor studies of age-at-onset in a sample ascertained for Parkinson disease affected sibling pairs: a cautionary tale
2007

Risk Factors and Age of Onset in Parkinson's Disease

Sample size: 542 publication Evidence: moderate

Author Information

Author(s): Jemma B. Wilk, Timothy L. Lash

Primary Institution: Boston University School of Medicine

Hypothesis

Do environmental risk factors like coffee drinking and smoking affect the age at which Parkinson's disease begins?

Conclusion

The study suggests that associations between coffee drinking, smoking, and age-at-onset of Parkinson's disease may be influenced by secular trends rather than direct causal relationships.

Supporting Evidence

  • The study found that the protective associations of coffee and smoking with Parkinson's disease risk may not translate to age-at-onset.
  • Previous studies suggested that coffee drinking and smoking could delay the onset of Parkinson's disease, but this study questions that inference.
  • The analysis indicates that observed associations may reflect secular trends rather than direct effects of the risk factors.

Takeaway

This study looks at how things like coffee and smoking might change when people get Parkinson's disease, but it finds that these factors might not really change when the disease starts.

Methodology

The study used data from the GenePD study, which involved affected sibling pairs with Parkinson's disease, to analyze the relationship between risk factors and age-at-onset.

Potential Biases

The study highlights risks of bias due to age-related factors influencing both exposure and outcome.

Limitations

The case-only design may not account for age differences between those exposed and unexposed to risk factors, leading to potential confounding.

Participant Demographics

Participants were born between 1901 and 1963 and diagnosed with Parkinson's disease between 1965 and 2002.

Statistical Information

Confidence Interval

95% CI for coffee drinking: 1.3 to 6.7; for current smoking: -9.9 to -2.9.

Digital Object Identifier (DOI)

10.1186/1742-7622-4-1

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