Weight-cycling over 6 years is associated with pain, physical function and depression in the Osteoarthritis Initiative cohort

Body weight significantly impacts health and quality of life, and is a leading risk factor for the development of knee osteoarthritis (OA). Weight cycling may have more negative health consequences compared to steady high or low weight. Using the Osteoarthritis Initiative dataset, we investigated the effects of weight cycling on physical function, quality of life, and depression over 72-months compared to stable or unidirectional body weight trajectories. Participants (n = 731) had knee OA and were classified as: (1) stable-low (BMI < 25), (2) stable-overweight (BMI = 25-29.9), and (3) stable-obese (BMI ≥ 30); (4) steady-weight-loss; (5) steady-weight-gain (weight loss/gain ≥ 2.2 kg every 2-years); (6) gain-loss-gain weight cycling, and (7) loss-gain-loss weight cycling (weight loss/gain with return to baseline), based on bi-annual assessments. We compared Knee Injury and Osteoarthritis Outcome Knee-Related Quality of Life, Function in Sports and Recreation, Physical Activity in the Elderly, Short Form SF-12, repeated chair rise, 20-m gait speed, and Center for Epidemiological Studies Depression using repeated-measures ANOVA. The steady weight loss group demonstrated the worst pain, physical function, and depressive symptoms over time (p's < 0.05). More research is needed to confirm these findings, and elucidate the mechanisms by which steady weight loss is associated with functional decline in knee OA.

Effects of Curcumin C3 Complex® on Physical Function in Moderately Functioning Older Adults with Low-Grade Inflammation - A Pilot Trial

BACKGROUND

Natural dietary compounds that can modulate the inflammation process have the potential to improve physical function through a number of biological pathways, and thus may represent an alternative approach to avert functional decline compared to more time-burdening lifestyle interventions. In this pilot trial, we tested the feasibility and explored the effect of a nutritional compound, Curcumin C3 Complex® for improving physical function and muscle strength in moderately functioning older adults with low-grade inflammation.

METHODS

Moderately functioning (short physical performance battery, SPPB <10) and sedentary older adults (>65 years) with low-grade systemic inflammation (c-reactive protein >1mg/dL) were randomized to receive Curcumin C3 Complex® (n=9) (1000mg/day) or placebo (n=8) groups for 12 weeks. All participants (age range: 66-94 years, 8 females and 9 males) underwent functional testing (SPPB and walking speed by the 400-meter walk test) and lower-limb strength (knee flexion and extension peak torque by the Biodex test) at baseline and 12 weeks. Venous blood was collected at baseline, 4, 8 and 12 weeks for safety blood chemistry analyses and biomarkers of inflammation.

RESULTS

A total of 17 participants were randomized and completed the study. Adherence was high (> 90%) and there were no adverse events reported or abnormal blood chemistries reported. Based on effect sizes, participants in the Curcumin C3 Complex® group demonstrated large effect sizes in the SPPB (Cohen's effect size d=0.75) and measures of knee extension (d=0.69) and flexion peak torque (d=0.82). Effect sizes for galectin-3 (d=-0.31) (larger decrease) and interleukin-6 (d=0.38) (smaller increase) were small in the Curcumin C3 Complex® group compared to placebo.

CONCLUSION

This pilot trial suggests that there were no difficulties with recruitment, adherence and safety specific to the study protocol. Preliminary findings warrant a Phase IIb clinical trial to test the effect of Curcumin C3 Complex® on physical function and muscle strength in older adults at risk for mobility disability.

Vitamin D, race, and experimental pain sensitivity in older adults with knee osteoarthritis

OBJECTIVE

Low circulating serum levels of 25-hydroxyvitamin D (referred to hereafter as vitamin D) have been correlated with many health conditions, including chronic pain. Recent clinical practice guidelines define vitamin D levels <20 ng/ml as deficient and levels of 21-29 ng/ml as insufficient. Vitamin D insufficiency, including the most severe levels of deficiency, is more prevalent in black Americans. Ethnic and race group differences have been reported in both clinical and experimental pain, with black Americans reporting increased pain. The purpose of this study was to examine whether variations in vitamin D levels contribute to race differences in knee osteoarthritis pain.

METHODS

The sample consisted of 94 participants (74% women), including 45 blacks and 49 whites with symptomatic knee osteoarthritis. Their average age was 55.8 years (range 45-71 years). Participants completed a questionnaire on knee osteoarthritis symptoms and underwent quantitative sensory testing, including measures of sensitivity to heat-induced and mechanically induced pain.

RESULTS

Blacks had significantly lower levels of vitamin D compared to whites, demonstrated greater clinical pain, and showed greater sensitivity to heat-induced and mechanically induced pain. Low levels of vitamin D predicted increased experimental pain sensitivity, but did not predict self-reported clinical pain. Group differences in vitamin D levels significantly predicted group differences in heat pain and pressure pain thresholds at the index knee and ipsilateral forearm.

CONCLUSION

These data demonstrate that race differences in experimental pain are mediated by differences in the vitamin D level. Vitamin D deficiency may be a risk factor for increased knee osteoarthritis pain in black Americans.