Impaired counterregulatory responses to hypoglycaemia following oral glucose in adults with cystic fibrosis.

AIMS/HYPOTHESIS: The aim of this study was to determine the mechanism(s) for hypoglycaemia occurring late following oral glucose loading in patients with cystic fibrosis (CF). METHODS: A 3 h 75 g OGTT was performed in 27 non-diabetic adults with CF who were classified based on this test as experiencing hypoglycaemia (glucose <3.3 mmol/l with or without symptoms or glucose <3.9 mmol/l with symptoms, n = 14) or not (n = 13). Beta cell function, incretin (glucagon-like peptide-1 [GLP-1] and glucose-dependent insulinotropic peptide [GIP]) and counterregulatory hormone responses (glucagon, catecholamines, growth hormone and cortisol) were assessed. RESULTS: The two groups did not differ in age, weight or BMI. There were more male participants and individuals with pancreatic exocrine insufficiency in the hypoglycaemia group. Fasting plasma glucose did not differ between the two groups (5.3 ± 0.16 vs 5.3 ± 0.10 mmol/l). Both fasting insulin (20.7 ± 2.9 vs 36.5 ± 4.8 pmol/l; p = 0.009) and C-peptide (0.38 ± 0.03 vs 0.56 ± 0.05 nmol/l; p = 0.002) were lower in those who experienced hypoglycaemia. Following glucose ingestion, glucose concentrations were significantly lower in the hypoglycaemia group from 135 min onwards, with a nadir of 3.2 ± 0.2 vs 4.8 ± 0.3 mmol/l at 180 min (p < 0.001). The test was terminated early in three participants because of a glucose level <2.5 mmol/l. Insulin and C-peptide concentrations were also lower in the hypoglycaemia group, while incretin hormone responses were not different. Modelling demonstrated that those experiencing hypoglycaemia were more insulin sensitive (439 ± 17.3 vs 398 ± 13.1 ml min-1 m-2, p = 0.074 based on values until 120 min [n = 14]; 512 ± 18.9 vs 438 ± 15.5 ml min-1 m-2, p = 0.006 based on values until 180 min [n = 11]). In line with their better insulin sensitivity, those experiencing hypoglycaemia had lower insulin secretion rates (ISRfasting: 50.8 ± 3.2 vs 74.0 ± 5.9 pmol min-1 m-2, p = 0.002; ISROGTT: 44.9 ± 5.0 vs 63.4 ± 5.2 nmol/m2, p = 0.018) and beta cell glucose sensitivity (47.4 ± 4.5 vs 79.2 ± 7.5 pmol min-1 m-2 [mmol/l]-1, p = 0.001). Despite the difference in glucose concentrations, there were no significant increases in glucagon, noradrenaline, cortisol or growth hormone levels. Adrenaline increased by only 66% and 61% above baseline at 165 and 180 min when glucose concentrations were 3.8 ± 0.2 and 3.2 ± 0.2 mmol/l, respectively. CONCLUSIONS/INTERPRETATION: Hypoglycaemia occurring late during an OGTT in people with CF was not associated with the expected counterregulatory hormone response, which may be a consequence of more advanced pancreatic dysfunction/destruction.

Relationships between perceived stress and health behaviors in a sample of working adults.

The study examined associations between perceived stress and fat intake, exercise, alcohol consumption, and smoking behaviors. Data were from surveys of 12,110 individuals in 26 worksites participating in the SUCCESS project (D. J. Hennrikus, R. W. Jeffery, & H. A. Lando, 1995), a study of smoking cessation interventions. Linear regression analyses examined cross-sectional associations between stress level and health behaviors. Analyses were stratified by gender and controlled for demographics. High stress for both men and women was associated with a higher fat diet, less frequent exercise, cigarette smoking, recent increases in smoking, less self-efficacy to quit smoking, and less self-efficacy to not smoke when stressed. Stress was not associated with alcohol intake. Findings suggest that the association between stress and disease may be moderated in part by unhealthy behaviors.

Are unrealistic weight loss goals associated with outcomes for overweight women?

OBJECTIVE: To examine cross-sectional correlates of current, goal, and dream weight and their prospective associations with weight loss in treatment. RESEARCH METHODS AND PROCEDURES: Goal and dream weights, demographic characteristics, and psychosocial factors were assessed by self-report questionnaire in 302 adult women enrolled in a weight loss trial. Height and weight were assessed at baseline, after 8 weeks of active treatment, and at 6- and 18-month follow-up. Regression techniques examined associations among baseline, goal, and dream weights, psychosocial factors, and treatment outcomes. RESULTS: On average, goal and dream weight losses were unrealistically high (-24% and -30%, respectively). High goals were associated with greater expected effort and greater expected reward but were not associated with psychological distress. Goal and dream weight losses were only weakly associated with behavioral or weight outcomes. An association between higher dream weight losses and greater weight loss at 18 months was the only outcome result to reach statistical significance. DISCUSSION: Results suggest that lack of realism in weight loss goals is not important enough to justify counseling people to accept lower weight loss goals when trying to lose weight.