Targeted dietary interventions to reduce pain in persistent post-traumatic headache among service members: Protocol for a randomized, controlled parallel-group trial.

INTRODUCTION:Post-traumatic headache (PTH) is common after traumatic brain injury (TBI), especially among active-duty service members (SMs), affecting up to 35% of patients with chronic TBI. Persistent PTH is disabling and frequently unresponsive to treatment and is often migrainous. Here, we describe a trial assessing whether dietary modifications to increase n-3 eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and reduce n-6 linoleic acid (LA), will alter nociceptive lipid mediators and result in clinical improvements in persistent PTH. METHODS:This prospective, randomized, controlled trial tests the efficacy, safety, and biochemical effects of targeted, controlled alterations in dietary n-3 and n-6 fatty acids in 122 adult SMs and military healthcare beneficiaries with diagnosed TBI associated with actively managed persistent frequent (>8 /month) PTH with migraine. Following a 4-week baseline, participants are randomized to one of two equally intensive dietary regimens for 12 additional weeks: 1) increased n-3 EPA + DHA with low n-6 LA (H3L6); 2) usual US dietary content of n-3 and n-6 fatty acids (Control). During the intervention, participants receive diet arm-specific study oils and foods sufficient for 75% of caloric needs and comprehensive dietary counseling. Participants complete daily headache diaries throughout the intervention. Clinical outcomes, including the Headache Impact Test (HIT-6), headache hours per day, circulating blood fatty acid levels, and bioactive metabolites, are measured pre-randomization and at 6 and 12 weeks. Planned primary analyses include pre-post comparisons of treatment groups on clinical measures using ANCOVA and mixed-effects models. Similar approaches to explore biochemical and exploratory clinical outcomes are planned. CLINICALTRIALS:gov registration: NCT03272399.