The highest quartile of sodium intake was associated with 2.07-fold higher risk of cardiovascular disease than seen in the lowest quartile (95% CI 1.16 to 3.71), Hirohito Sone, MD, PhD, of Niigata University in Japan, and colleagues found in a new study.
Within the Japanese cohort of people with hemoglobin A1c levels of at least 6.5%, each 1-g per day increase in sodium intake was associated with a 20% higher risk of heart and vascular disease (P=0.02).
These results "show that high dietary sodium intake is associated with an elevated incidence of cardiovascular disease in patients with type 2 diabetes, which supports current guidelines for patients with diabetes," the researchers concluded.
Although guidelines for diabetes care recommend reducing salt intake, the evidence has been based on studies of people without diabetes. Some work has suggested that reducing salt intake holds benefits for patients with type 2 diabetes, but the relationship between sodium intake and diabetes complications isn’t clear, the researchers said.
Sone and colleagues looked at data from 1,588 patients over 8 years of follow-up in the Japan Diabetes Complication Study, which involved 59 university and general hospitals in Japan. The prospective study set out to investigate the incidence of, and risk factors for macrovascular and microvascular complications of diabetes.
The mean dietary salt intake ranged from 2.8 g in the lowest quartile to 5.9 g in the highest quartile (current daily goals for sodium intake are 1.5 g per day in the U.S., 2.36 g per day in Europe, and 3.9 g per day in Japan).
When broken down by levels of blood sugar control, risk was dramatically elevated for patients in the top quartile of salt consumption compared with the bottom quartile if they had an HbA1c greater than 9% (HR 16.14 versus a nonsignificant HR 1.58).
- Risks of nephropathy, diabetic retinopathy, and all-cause mortality weren’t associated with sodium intake.
- With hemoglobin A1c levels of at least 6.5%, each 1-g per day increase in sodium intake was associated with a 20% higher risk of heart and vascular disease
Journal of Clinical Endocrinology & Metabolism: Horiakwa C, et al "Dietary sodium intake and incidence of diabetes complications in japanese patients with type 2 diabetes" J Clin Endocrinol Metab 2014; DOI: 10.1210/jc.2013-4315.