Active or Passive Smoking May Be Linked to Glucose Intolerance
on Tuesday, April 18 @ 13:54:12 CDT
Both active and passive smoking increase the risk of developing glucose intolerance, according to the results of a prospective cohort study.
"Smoking has been linked to impaired response to glucose tolerance tests and insulin resistance," write Thomas K. Houston, MD, from the Birmingham Veterans Affairs Medical Center in Alabama, and colleagues. "Although smoking cessation can result in modest weight gain, smoking is related to a more unhealthy distribution of upper body weight and greater waist:hip ratio. Smoking has also been associated with risk of chronic pancreatitis and pancreatic cancer, suggesting that tobacco smoke may be directly toxic to the pancreas."
The Coronary Artery Risk Development In young Adults (CARDIA) study began in 1985 to 1986 with recruitment of black and white men and women aged 18 to 30 years with no glucose intolerance at baseline. Participants were 1386 current smokers, 621 previous smokers, 1452 never smokers with reported exposure to secondhand smoke and 1113 never smokers with no exposure to secondhand smoke. The primary endpoint was time to development of glucose intolerance (glucose, >/= 100 mg/dL or taking antidiabetic drugs) during 15 years of follow-up.
At baseline, median age was 25 years, 55% of participants were women, and 50% were African American. During follow-up, glucose intolerance developed in 16.7% of participants. There was a graded association between smoking exposure and the incidence of glucose intolerance during the 15-year follow-up, which was 21.8% for smokers, 17.2% for never smokers with passive smoke exposure, 14.4% for previous smokers, and 11.5% for never smokers with no passive smoke exposure.
After adjustment for multiple baseline sociodemographic, biological, and behavioral factors, risk was still higher in current smokers (hazard ratio [HR], 1.65, 95% confidence interval [CI], 1.27 - 2.13) and never smokers with passive smoke exposure (HR, 1.35; 95% CI, 1.06 - 1.71) than in never smokers without passive smoke exposure. However, risk in previous smokers was similar to that in never smokers without passive smoke exposure.
"We found that tobacco exposure is associated with the development of glucose intolerance over a 15 year period, with a dose-response effect apparent," the authors write. "These findings support a role of both active and passive smoking in the development of glucose intolerance in young adulthood."
"Importantly, we identified passive tobacco exposure in never smokers as a new risk factor for glucose intolerance," the authors conclude. "If confirmed by further research, these findings provide further documentation of the deleterious effects of tobacco smoking, and policy makers may use them as additional justification to reduce exposure to passive smoke."
BMJ. Posted online April 6, 2006.
on Tuesday, April 18 @ 13:50:44 CDT
Long-term, biannual dietary intervention reduces risk for insulin resistance in children, according to the results of a randomized study.
"Insulin resistance, defined as an inadequate metabolic response to plasma insulin at normal concentrations, is promoted by obesity and high intake of saturated fat, and up to 30% of overweight or obese individuals develop insulin resistance," write Tuuli Kaitosaari, MD, from the University of Turku in Finland, and colleagues from the Special Turku Coronary Risk Factor Intervention Project for Children (STRIP) study. "Preventing obesity and sedentary lifestyle and supporting a healthy lifestyle are important preventive measures, particularly if started in childhood."
In this study, healthy 7-month-old infants (n = 1062) were randomized to the intervention (n = 540) and control groups (n = 522). The intervention consisted of biannual individualized counseling sessions for each child's family, aimed at minimizing children's exposure to known environmental risk factors for atherosclerosis. At 9 years of age in a random subgroup of 78 intervention children and 89 control children, a homeostasis model assessment of insulin resistance (HOMA-IR) index, serum lipids, blood pressure, and weight for height were determined.
Compared with the control children, the intervention children consumed less total fat (P = .002) and saturated fat (P < .0001) and had a lower HOMA-IR index (P = .02). Saturated fat intake was significantly correlated with HOMA-IR. Multivariate analyses revealed that the study group, but not saturated fat intake or other determinants of HOMA-IR (serum triglyceride concentration, weight for height, and systolic blood pressure), was significantly associated with HOMA-IR.
"This suggests that the beneficial effect of intervention on insulin sensitivity was largely, but not fully, explained by the decrease in saturated fat intake," the authors write. "The long-term biannual dietary intervention decreases the intake of total and saturated fat and has a positive effect on insulin resistance index in 9-year-old children."
The authors suggest that development of insulin resistance and possibly also atherosclerosis may be delayed or prevented by introducing relevant dietary and lifestyle habits in early childhood.
Diabetes Care. 2006;29:781-785