Cognitive deficits associated with impaired awareness of hypoglycaemia in type 1 diabetes.

AIMS/HYPOTHESIS: The aim of this study was to compare cognitive function in adults with type 1 diabetes who have impaired awareness of hypoglycaemia with those who have normal awareness of hypoglycaemia. A putative association was sought between cognitive test scores and a history of severe hypoglycaemia. METHODS: A total of 68 adults with type 1 diabetes were included: 33 had impaired and 35 had normal awareness of hypoglycaemia, as confirmed by formal testing. The groups were matched for age, sex and diabetes duration. Cognitive tests of verbal memory, object-location memory, pattern separation, executive function, working memory and processing speed were administered. RESULTS: Participants with impaired awareness of hypoglycaemia scored significantly lower on the verbal and object-location memory tests and on the pattern separation test (Cohen's d -0.86 to -0.55 [95% CI -1.39, -0.05]). Participants with impaired awareness of hypoglycaemia had reduced planning ability task scores, although the difference was not statistically significant (Cohen's d 0.57 [95% CI 0, 1.14]). Frequency of exposure to severe hypoglycaemia correlated with the number of cognitive tests that had not been performed according to instructions. CONCLUSIONS/INTERPRETATION: Impaired awareness of hypoglycaemia was associated with diminished learning, memory and pattern separation. These cognitive tasks all depend on the hippocampus, which is vulnerable to neuroglycopenia. The findings suggest that hypoglycaemia contributes to the observed correlation between impaired awareness of hypoglycaemia and impaired cognition.

Fear of hypoglycemia in women and men with type 1 diabetes.

BACKGROUND: Severe hypoglycemia is a serious complication of type1 diabetes feared by many who have the disease. OBJECTIVES: The aim of this study was to investigate specific fears related to hypoglycemia in adults with type 1 diabetes and to investigate how aspects of fear of hypoglycemia may differ between genders. METHODS: A cross-sectional study with questionnaires sent to 636 patients with type 1 diabetes, aged 18-75 years, who attended the outpatient clinic at St. Olavs Hospital, Trondheim, Norway. Fears related to hypoglycemia were assessed using the Hypoglycemia Fear Survey II Worry subscale (HFS-II-Worry). RESULTS: The response rate was 70% (N = 445, 216 women and 229 men). The mean HFS-II-Worry score was higher in women than in men (2.46 [SD = 0.80] vs. 2.22 [SD = 0.74], respectively; p < .001). Women scored higher than men in all items in the HFS-II-Worry, and women's average scores were statistically significantly higher in 5 of the 18 items after correction for multiple comparisons. The largest gender differences in mean scores occurred in the items "low blood glucose interfering with important things," "becoming upset and difficult," "difficulty thinking clearly," and "feeling lightheaded or dizzy." In both women and men, the highest mean scores appeared in the worry items "become hypoglycemic while sleeping" and "not having food available." DISCUSSION: In this sample of Norwegian adults with type 1 diabetes, women expressed more concerns about hypoglycemia than men. The highest HFS-II-Worry scores occurred in the same items in women and men, but the largest gender differences in mean scores appeared across a variety of other items, some of which were related to social esteem.

Impaired Awareness of Hypoglycemia in Adults With Type 1 Diabetes Is Not Associated With Autonomic Dysfunction or Peripheral Neuropathy.

OBJECTIVE: Impaired awareness of hypoglycemia (IAH) is a risk factor for severe hypoglycemia in people with insulin-treated diabetes; autonomic neuropathy has been suggested to underlie its development. The aim was to evaluate a putative association between IAH and autonomic dysfunction using novel and sensitive measures of autonomic neural function. RESEARCH DESIGN AND METHODS: Sixty-six adults with type 1 diabetes were studied, 33 with IAH and 33 with normal awareness of hypoglycemia (NAH), confirmed by formal testing. Participants were matched for age, sex, and diabetes duration. Clinical and laboratory evaluations included extensive autonomic function testing, peripheral nerve conduction studies, and quantitative sensory testing. Composite abnormality Z scores were used for group comparisons. RESULTS: The IAH and NAH group had similar median (interquartile range) age of 48 (14.5) vs. 47 (14.5) years, diabetes duration of 30 (13.5) vs. 31 (13.5) years, and mean ± SD HbA1c 7.8 ± 2.2% vs. 8.1 ± 1.9%, respectively. The autonomic composite Z score did not differ between the two groups (mean difference -0.15, 95% CI -0.46, 0.16; P = 0.33), nor did the thermal detection (mean difference 0.15, 95% CI -0.31, 0.61; P = 0.51) or nerve conduction scores (mean difference 0.03, 95% CI -0.43, 0.49; P = 0.89). CONCLUSIONS: In adults with type 1 diabetes, IAH was not associated with autonomic dysfunction or peripheral neuropathy.