Abstract
Few studies have evaluated the linkage between food cost and mortality among older adults. This study considers the hypothesis that greater food expenditure in general, and particularly on more nutritious plant and animal-derived foods, decreases mortality in older adults. This study uses the 1999–2000 Elderly Nutrition and Health Survey in Taiwan and follows the cohort until 2008, collecting 24-hr dietary recall data for 1781 participants (874 men and 907 women) aged 65 y or older. Using monthly mean national food prices and 24-hr recall, this study presents an estimate of daily expenditures for vegetable, fruit, animal-derived, and grain food categories. Participants were linked to the national death registry. Of the 1781 original participants, 625 died during the 10-y follow-up period. Among the 4 food categories, the fourth and fifth expenditure quintiles for vegetables and for fruits had the highest survival rates. After adjusting for co-variates, higher (Q4) vegetable and higher fruit (Q4) food expenditures referent to Q1 were significantly predictive of reduced mortality (HR = 0.55, 95% CI: 0.39-0.78 and HR = 0.64, 95% CI: 0.42–0.99, respectively) and the risk decreased by 12% and 10% for every NT$15 (US$0.50) increase in their daily expenditures. Animal-derived and grain food spending was not predictive of mortality. Greater and more achievable vegetable and fruit affordability may improve food security and longevity for older
Generated Summary
This study investigates the correlation between food expenditure, particularly on vegetables, fruits, and animal-derived foods, and all-cause mortality among older adults in Taiwan. The research utilized data from the 1999–2000 Elderly Nutrition and Health Survey in Taiwan, following a cohort of 1781 participants aged 65 years or older until 2008. The study estimated daily expenditures on various food categories (vegetables, fruits, animal-derived foods, and grains) based on 24-hour dietary recall data and national food prices. Participants were linked to the national death registry to assess mortality. The primary hypothesis was that increased expenditure on nutritious foods, such as vegetables and fruits, would correlate with decreased mortality, while expenditure on less nutritious foods might be linked to higher mortality. The study used a quantitative approach, employing statistical methods such as Cox proportional-hazards models to examine the relationship between food expenditures and mortality, adjusting for multiple covariates.
Key Findings & Statistics
- A total of 625 (35.9%) participants died during the 10-year follow-up period.
- The fourth and fifth expenditure quintiles for vegetables and fruits had the highest survival rates.
- Higher (Q4) vegetable and higher fruit (Q4) food expenditures were significantly predictive of reduced mortality after adjusting for co-variates.
- The HR for vegetable expenditure in Q4 was 0.55 (95% CI: 0.39-0.78) compared to Q1.
- The HR for fruit expenditure in Q4 was 0.64 (95% CI: 0.42–0.99) compared to Q1.
- The risk decreased by 12% and 10% for every NT$15 (US$0.50) increase in their daily expenditures for vegetables and fruits, respectively.
- The cumulative death rates were 68.1 and 39.9 per 1000 person-years in the first and fifth quintiles of vegetable expenditures, respectively.
- The lowest rate was 36.3 in the fourth quintile.
- In the crude model, the HRs for all-cause mortality of the participants significantly decreased as the expenditures of vegetables and fruits increased.
- The Q4 and Q5 for vegetable expenditure had HR values significantly lower than Q1 for all-cause mortality (Q4, HR = 0.55, 95% CI: 0.39-0.78; Q5, HR = 0.74, 95% CI: 0.50-1.08), and the dose-response relationship was significant.
- For fruits, Q3 and Q4 expenditures were associated with significantly lower mortality rates compared to Q1 (Q3, HR = 0.62, 95% CI: 0.42-0.92; Q4, HR = 0.64, 95% CI: 0.42-0.99), and the dose-response relationship remained significant in the model 1.
- When treating food expenditure as a continuous variable, every NT$15 increase in daily vegetable or fruit expenditure led to 12% or 10% reductions, respectively, in all-cause mortality, when holding total food and grains expenditures and potential co-variates constant.
- After excluding participants who died in the first year of follow-up, every NT$15 increase in daily vegetable expenditure caused a 16% reduction in all-cause mortality (HR = 0.84, 95% CI: 0.72, 0.99).
- For fruit, every NT$15 increase in daily fruit expenditure was associated with a 12% reduction in all-cause mortality (HR = 0.88, 95% CI: 0.77, 1.00).
Other Important Findings
- Animal-derived and grain food spending was not predictive of mortality.
- Participants aged 80 y or older, indigenous, or who lived alone were more likely to have lower expenditures on vegetables.
- The study found no identifiable association between animal or grain food costs and all-cause mortality.
- The daily dietary nutrient intakes for those whose vegetable expenditure in Q4 or Q5 were lower in saturated fat and higher in polyunsaturated fat, dietary fiber, Ca, Mg, K and vitamins A, E, B-6, and C.
Limitations Noted in the Document
- The study’s food costs were based on a 1-day food consumption recall, which might not reflect usual intake.
- One 24-hr dietary recall might result in a less precise measurement of usual food intake.
- Food prices were derived from national average monthly prices and did not consider regional price variations.
- The findings may not be extrapolated to countries at different stages of economic development or with different types of cultural food.
- The study cannot rule out the possibility that participants who acquired and consumed more than the food intake analysis identified incurred greater food expenditures.
Conclusion
The study concludes that greater vegetable and fruit expenditure is associated with reduced all-cause mortality among older Taiwanese adults. The findings suggest that increasing the affordability of these foods could improve food security and longevity, particularly for those with limited resources. The research highlights the significance of vegetable and fruit consumption, which are sources of many bioactive components. The study notes that there was no identifiable association between animal or grain food costs and all-cause mortality, contrary to the original hypothesis. The results emphasize the importance of integrating health economics and nutrition, particularly in the context of food security. The study also acknowledges that the relationship between food expenditures and dietary quality should be considered when calculating mortality risk. The study found that vegetable and fruit expenditures are higher than that for grains, but less than that for animal-derived foods. In the Taiwanese context, the study suggests that the cost of the main grain staple and the expenditure on animal products are not discriminant for mortality. This study indicates a greater dependence on dietary diversity or an integrated food pattern for fruit than for vegetable expenditure where the latter appears to have associations with mortality of its own. The study suggests that vegetable costs in Taiwan are a survival discriminator for older adults. It is also emphasized that the health benefits associated with greater vegetable and fruit intake may vary depending on the consumption amount, and that the fourth quintile for vegetable expenditure might represent optimal food expenditure. The study recommends that national nutrition policy in Taiwan should emphasize affordable fruits and vegetables to enhance food security and longevity among older adults.