Lifestyle and dietary interventions for Ménière’s disease

BACKGROUND: Ménière's disease is a condition that causes recurrent episodes of vertigo, associated with hearing loss and tinnitus. Lifestyle or dietary modifications (including reducing the amount of salt or caffeine in the diet) are sometimes suggested to be of benefit for this condition. The underlying cause of Ménière's disease is unknown, as is the way in which these interventions may work. The efficacy of these different interventions at preventing vertigo attacks, and their associated symptoms, is currently unclear. OBJECTIVES: To evaluate the benefits and harms of lifestyle and dietary interventions versus placebo or no treatment in people with Ménière's disease. SEARCH METHODS: The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE; Ovid Embase; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 14 September 2022. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and quasi‐RCTs in adults with Ménière's disease comparing any lifestyle or dietary intervention with either placebo or no treatment. We excluded studies with follow‐up of less than three months, or with a cross‐over design (unless data from the first phase of the study could be identified). DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Our primary outcomes were: 1) improvement in vertigo (assessed as a dichotomous outcome ‐ improved or not improved), 2) change in vertigo (assessed as a continuous outcome, with a score on a numerical scale) and 3) serious adverse events. Our secondary outcomes were: 4) disease‐specific health‐related quality of life, 5) change in hearing, 6) change in tinnitus and 7) other adverse effects. We considered outcomes reported at three time points: 3 to < 6 months, 6 to ≤ 12 months and > 12 months. We used GRADE to assess the certainty of evidence for each outcome. MAIN RESULTS: We included two RCTs, one related to diet, and the other related to fluid intake and sleep. In a Swedish study, 51 participants were randomised to receive 'specially processed cereals' or standard cereals. The specially processed cereals are thought to stimulate the production of anti‐secretory factor ‐ a protein that reduces inflammation and fluid secretion. Participants received the cereals for three months. The only outcome reported by this study was disease‐specific health‐related quality of life. The second study was conducted in Japan. The participants (223) were randomised to receive abundant water intake (35 mL/kg/day), or to sleep in darkness (in an unlit room for six to seven hours per night), or to receive no intervention. The duration of follow‐up was two years. The outcomes assessed were 'improvement in vertigo' and hearing. As these studies considered different interventions we were unable to carry out any meta‐analysis, and for almost all outcomes the certainty of the evidence was very low. We are unable to draw meaningful conclusions from the numerical results. AUTHORS' CONCLUSIONS: The evidence for lifestyle or dietary interventions for Ménière's disease is very uncertain. We did not identify any placebo‐controlled RCTs for interventions that are frequently recommended for those with Ménière's disease, such as salt restriction or caffeine restriction. We identified only two RCTs that compared a lifestyle or dietary intervention to placebo or no treatment, and the evidence that is currently available from these studies is of low or very low certainty. This means that we have very low confidence that the effects reported are accurate estimates of the true effect of these interventions. Consensus on the appropriate outcomes to measure in studies of Ménière's disease is needed (i.e. a core outcome set) in order to guide future studies in this area and enable meta‐analyses of the results. This must include appropriate consideration of the potential harms of treatment, as well as the benefits.