High sodium intake can double the risk of cardiovascular disease in type 2 diabetes patients – and increase it nearly 10-fold if the diabetes is poorly controlled, according to a recent study.
"It was suggested that dietary salt restriction as medical nutritional treatment would be useful to prevent complications of diabetes in patients with type 2 diabetes," Chika Horikawa of the University of Niigata, Japan, and her colleagues reported online (J. Clin. Endocrinol. Metab. 2014 July 22 [doi:10.1210/jc.2013-4315]).
The researchers assessed mean daily sodium intake from a baseline dietary survey of 1,588 participants, aged 40-70 years, with type 2 diabetes and hemoglobin A1c levels of at least 6.5%. The participants were recruited from 59 university and general hospitals in Japan and then tracked from intake, from January 1995 to March 1996, until March 2003 for cardiovascular disease, overt nephropathy, diabetic retinopathy, and all-cause mortality.
Over the 8 years of follow-up, cardiovascular disease occurred at a rate of 13.61 incidents/1,000 patient-years. Participants consuming the highest quartile of sodium – a mean 5.9 g/day – were twice as likely (hazard ratio, 2.07) as those consuming the lowest quartile – a mean 2.8 g/day – to develop cardiovascular disease, a significant difference. A sodium intake in the second and third quartiles increased cardiovascular disease risk 1.70 and 1.47 times, respectively, compared to the first quartile.
Patients with HbA1c greater than 9% and consuming sodium in the highest quartile were 9.91 times more likely to develop cardiovascular disease than were those in the first quartile with HbA1c less than 9%. The researchers found no association between sodium intake and risk of overt nephropathy, diabetic retinopathy, or all-cause mortality.
The research was funded by Honjo International Scholarship Foundation, the University of Tsukuba Research Infrastructure Support Program, the Japan Society for the Promotion of Science and the Japanese Ministry of Health, Labor and Welfare. The authors had no disclosures.