Krill Oil for Pain in Elders (KOPE): Protocol for a Pilot, Double-Blind, Randomized Controlled Trial Assessing Feasibility and Acceptability of 4 g/d Krill Oil Supplementation in Older Adults with Chronic Musculoskeletal Pain and Mobility Limitations

Mobility limitations due to chronic musculoskeletal pain are a major contributor to disability in older adults, yet current pharmacological treatments often have limited efficacy and increase the risk of polypharmacy. Omega (ω)-3 polyunsaturated fatty acids (PUFAs), particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have demonstrated anti-inflammatory and analgesic properties, but are under-consumed among older U.S. adults. Krill oil, a marine-derived source of EPA and DHA with enhanced bioavailability compared to typical fish oils and additional bioactive compounds such as astaxanthin and choline, may offer a promising nutritional intervention. This pilot study will assess the feasibility and acceptability of a 3-month randomized, double-blind, placebo-controlled trial of krill oil supplementation (4 g/day: 1,288 mg EPA+DHA, 0.45 mg astaxanthin, 320 mg choline) versus placebo (mixed vegetable oils) in 40 community-dwelling adults aged ≥60 years with chronic musculoskeletal pain. Primary outcomes include feasibility (recruitment, retention, adherence) and acceptability (participant satisfaction). Secondary outcomes include changes in the omega-3 index, ω-6/ω-3 ratio, and inflammation (hs-CRP), as well as exploratory changes in pain intensity and functional interference, and physical function (Short Physical Performance Battery, 6-Minute Walk Test). Findings will inform the design of future fully powered trials that may ultimately contribute to the evidence for omega-3 supplementation as a non-pharmacological strategy to support healthy aging and functional independence in older adults.