NEW YORK (Reuters Health) – Diabetes is an independent risk factor for atrial fibrillation in women, U.S. investigators report in the October issue of Diabetes Care.

The disease is also associated with atrial fibrillation in men, but in adjusted analyses the increased risk was not statistically significant, Dr. Gregory A. Nichols, at the Kaiser Permanente Center for Health Research in Portland, Oregon, and co-authors report.

While the link between diabetes and atrial fibrillation is well known, a statement from Kaiser Permanente notes that this study, which involved nearly 35,000 patients followed for roughly 7 years, is the first “to isolate the effect of diabetes” and confirm its independent impact.

Dr. Nichols and his team identified 17,372 patients in the company’s diabetes registries in Oregon and Washington and an equal number of matched controls.

At baseline, the prevalence of atrial fibrillation was higher among those with diabetes (3.6% vs 2.5%, p < 0.0001). While prevalence increased with age in both groups, the increase was steeper among diabetics, and particularly among women.

At the end of follow up in the 16,057 patients who were free of atrial fibrillation at baseline, the age/sex adjusted incidence rates of atrial fibrillation per 1000 person-years were 9.1 in diabetics and 6.6 in non-diabetics. Thus, the authors point out, the age/gender adjusted relative risk of atrial fibrillation was 38% higher in diabetics. After adjustment for other risk factors as well, patients with diabetes had a 16% greater risk of atrial fibrillation.

The adjusted relative risk was 30% among male diabetics vs 52% among female diabetics. “After full adjustment for other risk factors,” the hazard ratio for atrial fibrillation in women with diabetes was 1.26, whereas in men with diabetes the hazard ratio was 1.09.

Other factors significantly associated with atrial fibrillation included white race, high systolic blood pressure, ischemic heart disease, valvular heart disease, hypertension, and heart failure.

The authors theorize that “cardiac autonomic dysfunction may an important mechanism for the increased propensity for atrial fibrillation in diabetes, and warrants further study.”