Antioxidant vitamins and mortality in older persons: findings from the nutrition add-on study to the Medical Research Council Trial of Assessment and Management of Older People in the Community.
BACKGROUND
Older persons are at risk of both poor nutrition and increased oxidative stress. Plasma ascorbate concentrations fall with increasing age, and concentrations of other antioxidants may also be reduced.


OBJECTIVE
The goal was to examine the association between antioxidants and mortality in older persons.


METHODS
We randomly selected persons aged 75-84 y from the lists of 51 British family practitioners taking part in a randomized trial of assessment of older persons. A total of 1214 participants provided a blood sample and were interviewed about their usual diet with the use of a food-frequency questionnaire. Statistical analyses were based on deaths after a median of 4.4 y of follow-up, and hazard ratios were estimated for quintiles of dietary or blood antioxidants.


RESULTS
We found strong inverse trends for blood ascorbate concentrations with all-cause and cardiovascular disease mortality, which were only marginally reduced after adjustment for confounders or supplement use. Those in the lowest fifth (< 17 micromol/L) had the highest mortality, whereas those in the highest fifth (> 66 micromol/L) had a mortality risk nearly half that (hazard ratio = 0.54; 95% CI: 0.34, 0.84). Similar results were found after the exclusion of those subjects with cardiovascular disease or cancer at baseline (hazard ratio = 0.51; 0.28, 0.93). In fully adjusted models, there was no evidence for an influence of alpha-tocopherol, beta-carotene, or retinol on total mortality. Dietary antioxidants measured by the food-frequency questionnaire were not associated with all-cause or cardiovascular disease mortality.


CONCLUSIONS
Low blood vitamin C concentrations in the older British population are strongly predictive of mortality.
Fletcher
Astrid E
AE
Centre for Ageing and Public Health, London School of Hygiene and Tropical Medicine, United Kingdom. astrid.fletcher@lshtm.ac.uk
Breeze
Elizabeth
E
Shetty
Prakash S
PS
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D000975:Antioxidants / Q000008:administration & dosage* / Q000032:analysis; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000097:blood; D002318:Cardiovascular Diseases / Q000401:mortality; D004032:Diet; D015930:Diet Records; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008297:Male; D009026:Mortality; D015596:Nutrition Assessment; D009747:Nutritional Physiological Phenomena; D016016:Proportional Hazards Models; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014801:Vitamin A / Q000097:blood; D014815:Vitamins / Q000008:administration & dosage*; D024502:alpha-Tocopherol / Q000097:blood; D019207:beta Carotene / Q000097:blood
D000975:Antioxidants; D014815:Vitamins; D019207:beta Carotene; D014801:Vitamin A; D024502:alpha-Tocopherol; D001205:Ascorbic Acid