Low plasma carotenoids and skeletal muscle strength decline over 6 years

Abstract

Background: Higher intake of fruits and vegetables appears to protect against inflammation, poor physical performance, and disability, but its relationship with muscle strength is unclear. We examined the association between total plasma carotenoids, an indicator of fruit and vegetable intake, and changes in muscle strength over a 6-year follow-up in the participants aged 65 years and older in the InCHIANTI study, a population-based study in Tuscany, Italy.

Methods: Plasma carotenoids were measured at enrollment (1998-2000). Hip, knee, and grip strength were measured at enrollment and 6 years later (2004-2006) in 628 of the 948 participants evaluated at baseline. Poor muscle strength was defined as the lowest sex-specific quartile of hip, knee, and grip strength at enrollment. The main outcome was poor muscle strength at the 6-year follow-up visit among those participants originally in the upper three quartiles of strength at enrollment.

Results: Overall, 24.9% (110/441), 25.0% (111/444), and 24.9% (118/474) participants developed poor hip, knee, and grip strength, respectively. After adjusting for potential confounders, participants in the lowest versus the highest quartile of total plasma carotenoids at enrollment were at higher risk of developing poor hip (odds ratio [OR] = 3.01, 95% CI, 1.43-6.31, p =.004), knee (OR = 2.89, 95% CI, 1.38-6.02, p =.005), and grip (OR = 1.88, 95% CI, 0.93-3.56, p =.07) muscle strength at the 6-year follow-up visit.

Conclusion: These findings suggest that older community-dwelling adults with lower plasma carotenoids levels, a marker of poor fruit and vegetable intake, are at a higher risk of decline in skeletal muscle strength over time.

Figure 1

Percentage of participants who fell in a worse quartile of hip (a), knee (b) and grip (c) muscle strength from baseline to 6-year follow-up according to baseline strength and carotenoids level quartile.

Figure 1

Percentage of participants who fell in a worse quartile of hip (a), knee (b) and grip (c) muscle strength from baseline to 6-year follow-up according to baseline strength and carotenoids level quartile.

Figure 1

Percentage of participants who fell in a worse quartile of hip (a), knee (b) and grip (c) muscle strength from baseline to 6-year follow-up according to baseline strength and carotenoids level quartile.

Figure 2

Relationship between total plasma carotenoids (in quartiles) with change in hip, knee and grip knee strength between enrollment and 6-year follow-up visit, adjusted by age, sex, and strength at enrollment (Tests for linear trend, P = 0.0007 for hip strength, P = 0.0006 for knee strength and P = 0.04 for grip strength). * Age- Sex- and Baseline Muscle Strength adjusted.