Chinese adults who consume greater levels of carotenoids, including foods rich in beta-carotene, lycopene and lutein, are less likely to experience hip fracture vs. those with a diet that includes less of the antioxidants, according to findings from a case-control study.
“In vitro studies and animal experiments have demonstrated the potential role of carotenoids in preventing bone loss through decreasing oxidative stress,” Yu Ming Chen, MD, PhD, with the department of statistics and epidemiology at Sun Yat-sen University School of Public Health in Guangzhou, China, and colleagues wrote in the study background. “Few epidemiological studies have also reported favorable associations of carotenoids in the diet or blood with bone mineral density and the risk for osteoporosis. However, conflicting associations have been found between carotenoids and fracture risk, especially for individual carotenoids.”
Chen and colleagues analyzed data from 1,070 Chinese adults from Guangdong province aged 55 to 80 years with hip fractures diagnosed within 2 weeks of recruitment, along with 1,070 controls matched by age and sex, between June 2009 and August 2015 (793 women; mean age, 71 years). Participants completed in-person interviews and a 79-item food frequency questionnaire that assessed carotenoid intake. Researchers calculated intake of five individual carotenoids according to the U.S. Department of Agriculture national nutrient database of 2008: alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene and lutein/zeaxanthin. Participants were stratified by sex-specific quartiles based on distribution of total or specific carotenoid intakes, with the lowest quartile group treated as a reference. Researchers used logistic regression analyses to assess the associations between consumption of total and specific carotenoids and hip fracture risk.
Within the hip fracture group, 715 had femoral neck fractures and 355 had intertrochanteric fractures. Mean energy-adjusted intake of total carotenoids was 10.7 mg per day for hip fracture patients and 13.9 mg per day for controls. Median total carotenoid intake in the highest quartile was 22.38 µg per day for cases and 23.06 µg per day for controls, and median total carotenoid intake for the lowest quartile was 6.41 µg per day for cases and 6.02 µg per day for controls.
Researchers found that higher intakes of both total and some specific carotenoids (including beta-carotene, beta-cryptoxanthin and lutein/zeaxanthin) were associated with a lower risk for hip fracture (P for trend < .01). Compared with participants in the lowest quartile of carotenoids intake, the adjusted ORs for hip fracture risk for the highest quartile were 0.44 for total carotenoids (95% CI, 0.29-0.68), 0.5 for beta-carotene (95% CI, 0.29-0.69), 0.55 for beta-cryptoxanthin (95% CI, 0.38-0.8) and 0.4 for lutein/zeaxanthin (95% CI, 0.27-0.59). There were no between-group differences when stratified by sex and BMI, and further adjustment for potassium intake did not change the associations, according to researchers.
Researchers observed no associations between alpha-carotene and lycopene intakes and hip fracture risk after adjustment for various confounding variables.
The researchers noted that some biological mechanisms might explain the inverse associations between dietary carotenoids intake and bone health.
“Carotenoids can reduce oxidative stress levels in the body by scavenging singlet oxygen and peroxyl radicals,” the researchers wrote. “Antioxidants can suppress the expression of the receptor activator NF-kB ligand (RANKL) and thus suppress osteoclastic differentiation, promote osteoblast mineralization and stimulate the alkaline phosphatase activity of osteoblasts.” – by Regina Schaffer
Disclosures: The authors report no relevant financial disclosures.