Nutritional status and risk of amyotrophic lateral sclerosis in Japan

Only a few human studies have reported the relationship between dietary factors and the risk of amyotrophic lateral sclerosis (ALS). We therefore analyzed the relationship between macronutrients (carbohydrate, protein and fat) and the risk of ALS using a case-control study in Japan. The study comprised 153 ALS patients diagnosed by the El Escorial World Federation of Neurology criteria, and 306 gender- and age- matched controls randomly selected from the general population. A self-administered food frequency questionnaire was used to estimate pre-illness intakes of food groups and nutrients. The strength of association between ALS and a potential risk factor was assessed by calculating odds ratios (ORs) and 95% confidence intervals (CIs). A high intake of carbohydrate was significantly associated with an increased risk of ALS (adjusted OR = 2.14, 95% CI 1.05-4.36; the highest versus the lowest tertile). ORs for the second and third tertile of total fat were 0.57 and 0.41 (95% CI 0.21-0.80), respectively. ORs for the highest tertile of intake versus the lowest were 0.41 (95% CI 0.21-0.80) for total fat, 0.30 (95% CI 0.16-0.5) for saturated fatty acids (SFAs), 0.35 (95% CI 0.18-0.69) for monounsaturated fatty acids (MUFAs) and 0.58 (95%CI 0.40-0.96) for polyunsaturated fatty acids (PUFAs). Our findings suggest that high intakes of carbohydrate and low intakes of fat and some kinds of fatty acids may, when combined, increased the risk of ALS.