The effect of salt substitution on frequency and severity of headache: results from the SSaSS cluster-randomised controlled trial of 20,995 participants

• Published in: European journal of clinical nutrition 2024-05, Vol.78 (5), p.401-406
• Main Authors: Haghdoost, Faraidoon, Gnanenthiran, Sonali R., Shan, Sana, Kaistha, Prachi, Huang, Liping, Tian, Maoyi, Liu, Yishu, Yin, Xuejun, Zhang, Xinyi, Hao, Zhixin, Wu, Yangfeng, Di Tanna, Gian Luca, Neal, Bruce, Rodgers, Anthony
• Format: Article
• Language: English
• Subjects: 692/308/2778; 692/308/575; 692/499; 692/699/375/1370; 692/699/75/243; Aged; Blood pressure; Cardiovascular diseases; China - epidemiology; Chlorine compounds; Clinical Nutrition; Clusters; Diet, Sodium-Restricted - methods; Epidemiology; Female; Headache; Headaches; Humans; Hypertension; Internal Medicine; Male; Medicine; Medicine & Public Health; Metabolic Diseases; Middle Aged; Neurological diseases; Potassium; Potassium chloride; Potassium salts; Public Health; Salt; Salts; Severity of Illness Index; Signs and symptoms; Sodium; Sodium chloride; Sodium Chloride, Dietary - administration & dosage; Stroke; Substitutes
• ISSN: 0954-3007; 1476-5640; 1476-5640
• DOI: 10.1038/s41430-024-01419-7

Background Headache is one of the most common neurological symptoms. Headache disorders are associated with a high global burden of disease. Prior studies indicate that short-to-medium term sodium reduction reduces headache symptom. This study evaluated the effects of long-term reduced-sodium, added-potassium salt on headache frequency and severity in rural China. Methods The Salt substitute and stroke study (SSaSS) was an open-label cluster-randomised trial in rural China designed to evaluate the effect of salt substitution on mortality and cardiovascular events. Participants included adults with a history of prior stroke and those aged ≥60 years with uncontrolled high blood pressure (BP). Villages were randomly assigned in a 1:1 ratio either to intervention with salt substitute (75% sodium chloride and 25% potassium chloride by mass) or to control with continued use of regular salt (100% sodium chloride). In this pre-specified analysis, between-group differences in headache frequency and severity were evaluated. The study was registered with ClinicalTrials.gov (identifier number: NCT02092090). Results A total of 20,995 participants were included in the trial (mean age 64.3 years, 51% female, mean follow-up 4.7 years). At final follow-up at the end of the study, headache outcome data including frequency and severity of headaches was available for 16,486 (98%) of 16,823 living participants. Overall, 4454/16,486 (27%) individuals reported having headache: 27.4% in the intervention group (2301/8386) vs 26.6% in the control group (2153/8100) (RR 1.04, 95% CI: 0.93, 1.16, p  = 0.48). There was no difference in headache severity between intervention and control groups ( p  = 0.90). Conclusion Long term salt substitution did not reduce the frequency or severity of headaches in this population.