Cigarette smoking and cerebral microvasculature in patients with type 1 diabetes: a pilot study

Abstract

Introduction. A decrease in vasomotor reactivity reserve (VMRr) or an increase in pulsatility index (PI) are the early signs of cerebral microangiopathy in type 1 diabetes. Cigarette smoking is a risk factor for microvascular complications of type 1 diabetes, but cigarette smokers are routinely excluded from studies on VMRr or PI in type 1 diabetes (T1DM) and there is no evidence of any significant impact of smoking on these variables in T1DM. Therefore, we aimed to assess the impact of cigarette smoking on VMRr and PI in these patients.

Methods. VMRr and PI of the middle cerebral artery were measured with Transcranial Doppler in 79 patients with T1DM (median age 33.0 years, range 20–51, 44% males) without a history of cerebrovascular events, coronary heart disease or carotid stenosis. The relationship between cigarette smoking (n = 20, mean pack-years 9.4 ± 6.1) and VMRr, PI, concomitant risk factors, medications and the presence of systemic microvascular complications were analysed.

Results. Smokers and non-smokers did not differ in terms of their clinical characteristics, with an exception of higher circadian insulin demand in smokers (60 ± 12.9 v. 49.2 ± 14.2 units; p = 0.004). A correlation between pack-years and PI (r = 0.6, p = 0.004), but not with VMRr, was found in smokers. However, no significant differences between smokers and non-smokers were found regarding either VMRr (mean 85.9 ± 20% v. 84.1 ± 20.1%; p = 0.74) or PI (median 0.85, range 0.61–1.09 v. 0.88, range 0.48–1.52; p = 0.2).

Conclusions. We did not prove any significant impact of smoking on VMRr in T1DM patients, but the association between pack-years and PI may indicate the negative impact of intensive cigarette smoking on the cerebral microvasculature in type 1 diabetes.