The effects of serum beta-carotene concentration and burden of inflammation on all-cause mortality risk in high-functioning older persons: MacArthur studies of successful aging.
BACKGROUND
It remains unclear to what extent the associations between low serum beta-carotene concentration and increased risk for cardiovascular disease and cancers are attributable to inflammation. The objective of this study was to evaluate simultaneously the effects of serum beta-carotene concentration and inflammation on the subsequent all-cause mortality risk in high-functioning older persons.


METHODS
The authors conducted a prospective cohort study using information from 672 participants from the MacArthur Studies of Successful Aging. Baseline information was obtained for serum concentrations of beta-carotene, C-reactive protein, interleukin-6, cholesterols, and albumin; body mass index; waist:hip ratio; prevalent medical conditions; health behaviors; and medications. Sex-specific univariate and multivariate logistic regression analyses were used to study the effects of low beta-carotene, high inflammation burden, or both on 7-year all-cause mortality rates while adjusting for other confounders.


RESULTS
The serum beta-carotene concentration was inversely associated with C-reactive protein and interleukin-6 levels. After adjustment for inflammation markers and other covariates, the relative risks for low beta-carotene for the 7-year all-cause mortality risk were 2.30 (95% confidence interval [CI], 1.23 to 4.31) in men and 0.85 (95% CI, 0.42 to 1.75) in women. Compared with men with high beta-carotene levels and low inflammation, the multiply adjusted relative risk for low beta-carotene and high inflammation burden was 3.78 (95% CI, 1.69 to 8.47) in men.


CONCLUSIONS
Low levels of serum beta-carotene are independently associated with an increased all-cause mortality risk in older men, even after adjustment for the effects of inflammation and other risk factors. In men, but not women, a synergistic effect occurs between low beta-carotene concentration and high inflammation burden in predicting higher mortality rates.
Hu
Peifeng
P
Multicampus Program in Geriatric Medicine and Gerontology, UCLA School of Medicine, 10945 Le Conte Avenue, Suite 2339, Los Angeles, CA 90095-1687, USA. phu@mednet.ucla.edu
Reuben
David B
DB
Crimmins
Eileen M
EM
Harris
Tamara B
TB
Huang
Mei-Hua
MH
Seeman
Teresa E
TE
D000368:Aged; D002097:C-Reactive Protein / Q000032:analysis; D005260:Female; D006801:Humans; D007249:Inflammation / Q000150:complications*; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D009026:Mortality; D011446:Prospective Studies; D019207:beta Carotene / Q000097:blood*
D015850:Interleukin-6; D019207:beta Carotene; D002097:C-Reactive Protein