Age 85+ years accelerates large-fiber peripheral nerve dysfunction and diabetes contributes even in the oldest-old: the Women's Health and Aging Study.

BACKGROUND: Both diabetes mellitus and advancing age are associated with peripheral nerve dysfunction (PND). However, the independent and potentially synergistic effects of these factors in old age are poorly described, especially among the oldest-old and among people with an existing disability.
METHODS: A total of 894 women aged 65+ years participating in the Women's Health and Aging Study received a baseline home interview and clinical examination during which PND was evaluated by the Vibratron II. Age and diabetes were examined in relation to the level of PND (normal, mild, moderate, or severe). Height, alcohol consumption, smoking, report of neurologic symptoms, and diabetes duration were examined as potential confounders.
RESULTS: Eighteen percent of the sample reported diabetes, 42% had normal nerve function, and 23.9%, 14.5%, and 19.5% had mild, moderate, and severe PND, respectively. Women aged 85+ years had 6.5, 7.5, and 13.3 times the odds of mild, moderate, and severe PND relative to women aged 65-74 years, adjusted for diabetes and height. Women who reported diabetes had 1.8, 2.4, and 1.6 times the risk of mild, moderate, and severe PND relative to those who did not, adjusted for age and height. No interaction between age and diabetes was observed.
CONCLUSIONS: Age is strongly associated with decrements in large-fiber peripheral nerve function in disabled women aged 65+ years, with greatly accelerated risk among those aged 85+ years. Despite the overwhelmingly strong effects of advancing age on PND in this cohort, diabetes remains a significant correlate of PND. Future studies may determine whether prevention or control of diabetes is effective in reducing the occurrence of PND in old age and whether a reduction in PND will translate into reduced disability in this age group.