IJE Advance Access originally published online on January 4, 2006
International Journal of Epidemiology 2006 35(2):418-426; doi:10.1093/ije/dyi296
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Article |
Diet synergies and mortalitya population-based casecontrol study of 32 462 Hong Kong Chinese older adults
1 Department of Community Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
2 Department of Health, Kowloon, Hong Kong, China
* Corresponding author. Department of Community Medicine, 5/F Academic and Administration Block, University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China. E-mail: gmleung{at}hku.hk
Background Food and drink are not consumed in isolation and can have complimentary effects enhancing or blocking the overall uptake of nutrients. We investigated how combinations of foods, drinks, and smoking affected mortality.
Method Adjusted logistic regression was used to assess the joint effect of healthy foods, less healthy foods, smoking, and alcohol use on mortality in a casecontrol study of all Chinese adults aged 60 or over who died in 1998; 21 494 dead cases (81% of all registered deaths) and 10 968 live controls were included.
Results There was a significant trend of increasing all-cause mortality risk with decreasing healthy food consumption (P < 0.001), and the increase in risk was significantly steeper for people with high intakes of less healthy food (P for interaction <0.001). There was a steeper risk from increasing less healthy food intake in ever-smokers and people not drinking tea regularly (P < 0.001), while the J-shaped relationship between alcohol and mortality differed in shape with level of less healthy food intake.
Conclusion Intake of some dietary items may modify the effect of others. An analysis framework explicitly recognizing complementary and potentially synergistic effects of food, drinks, and smoking could enhance our understanding of dietary epidemiology.
Keywords Diet, synergy, mortality, smoking, older adults, casecontrol
Accepted 29 November 2005