The impact of 3-year changes in lifestyle habits on metabolic syndrome parameters: the D.E.S.I.R Study:

Metabolic parameters in smokers undergoing smoking reduction

Introduction

Few human studies have explored the mechanisms of smoking-induced insulin resistance. Aims: To prospectively examine the metabolic changes of smoking reduction.

Methods

Cigarette smokers (n = 22; ½-2 packs per day) were enrolled in a smoking reduction program (counseling plus bupropion × 8 weeks; Phase I) followed by monitoring only (no counseling or bupropion × 16 weeks; Phase II). We serially measured exhaled carbon monoxide (CO) and urine nicotine metabolites; fat distribution, and metabolic parameters by hyperinsulinemic clamps including hepatic glucose output (HGO) and indirect calorimetry, adjusted for total caloric intake and expenditure.

Results

CO and nicotine metabolite levels fell with smoking reduction during Phase I (all p < 0.05), without any further changes through Phase II. Central-to-peripheral fat ratio increased during Phase I, but then fell during Phase II (all p < 0.05). Over 24 weeks, basal HGO fell (p = 0.02); and falling CO and nicotine metabolite levels correlated inversely with changes in glucose oxidation, and directly with changes in weight (all p < 0.05).

Conclusions

Smoking reduction produced a transient worsening of central fat redistribution followed by a more significant improvement; along with other net beneficial metabolic effects.

Impact of objectively measured sedentary behaviour on changes in insulin resistance and secretion over 3 years in the RISC study: interaction with weight gain

AIMS

The importance of reducing sedentary time is increasingly being recognized in the prevention of diabetes and cardiovascular disease. Despite this, the prospective association between sedentary time and physical activity with insulin sensitivity and cardiometabolic risk factors has been little studied.

METHODS

In an analysis of data from the European RISC study, sedentary time and time spent in activity of moderate or vigorous intensity were assessed by accelerometry at baseline in 313 men and 414 women, aged 30-60 years, with insulin sensitivity as measured by euglycaemic-hyperinsulinaemic clamp. Three years later, cardiometabolic risk factors (anthropometry, glucose, insulin, lipids) were available for 549 participants.

RESULTS

In cross-sectional analyses using baseline data, after adjusting for age, gender, recruitment centre and time spent in activity of moderate or vigorous intensity, significant unfavourable associations were observed between higher sedentary time with body weight, HDL cholesterol, triglycerides, clamp-measured insulin sensitivity and insulin secretion (all P(trend)<0.002). Sedentary time remained significantly associated with insulin secretion after adjusting for insulin sensitivity (P(trend)=0.02). In longitudinal analyses, higher baseline sedentary time was associated with 3-year increases in fasting glucose, fasting insulin and the HOMA insulin-resistance index score for the 50% of the study population who increased their BMI by at least 0.3 kg/m(2) (all P(trend)<0.01); these relationships remained significant after adjusting for time spent in activity of moderate or vigorous intensity. The 3-year increase in insulin secretion was lower in those spending more time doing activity of moderate or vigorous intensity (P(trend)=0.03).

CONCLUSION

These prospective data suggest that less sedentary behaviour may partly counteract some of the negative effects of increasing body weight on glucose-insulin homoeostasis.

Weight gain and risk of impaired fasting glucose after smoking cessation

BACKGROUND

Observation of early changes in fasting plasma glucose level induced by post-smoking cessation weight gain is useful in predicting the risks of diabetes mellitus (DM) and impaired fasting glucose (IFG). We investigated the effect of post-smoking cessation weight gain on early changes in the risk of a high fasting plasma glucose (IFG) level (≥100 mg/dL).

METHODS

In 946 subjects who underwent repeated health examinations after smoking cessation, changes in body mass index (BMI) and the odds ratio (OR) for IFG risk (adjusted for sex, age, BMI, fasting plasma glucose at year 1, and alcohol consumption) were calculated every year for 3 years after smoking cessation.

RESULTS

After smoking cessation, the rate of BMI increase significantly increased in quitters: 2.36% at year 2 (never smokers: 0.22%, current smokers: 0.39%) and 0.46% at year 3 (never smokers: 0.14%, current smokers: 0.32%). However, it decreased by 0.15% at year 4 (never smokers: 0.12%, current smokers: 0.26%). The ORs for quitters did not significantly increase at any time during the follow-up period. However, among quitters who had smoked at least 20 cigarettes per day, it was significantly higher (OR 1.51, 95% confidence interval 1.1-2.01 at year 1 and 1.71, 1.23-2.38 at year 2).

CONCLUSIONS

The time course of the risk of IFG after smoking cessation was similar to that for the rate of BMI increase. In contrast to the findings of previous reports, the increase in IFG risk after smoking cessation was brief and disappeared in the absence of a significant increase in BMI.

Coronary disease risk and fasting glucose levels in a non-diabetic population

We addressed whether or not the risk of coronary heart disease (CHD) in non-diabetic persons is linear at the lower end of fasting glucose levels. Middle-aged Turkish adults (n=2893) free from diabetes and CHD at baseline were studied prospectively over a 7.6-year follow-up. Participants with fasting glucose measurements were analyzed in 3 groups separated by 90 mg/dl and 110 mg/dl limits. Outcomes were analyzed by Cox regression. Cox regression for CHD incidence (n=374) showed an increased age-adjusted risk in the <90 mg/dl fasting glucose group (n=788) [HR 1.32 (1.03; 1.68)], compared with the 90-110 mg/dl group after adjustment for sex, age and the glucose groups. Further adjustment for waist circumference, C-reactive protein and conventional risk factors attenuated the HR to 1.27 (p=0.077). The risk profile in the low-glucose group could not be accounted for by age, smoking status, systolic blood pressure or fasting insulin levels but tended to show higher levels of circulating C-reactive protein. The increased CHD risk observed in individuals with lower compared with higher normal glucose concentrations is likely to be related to an associated pro-inflammatory state.

Cigarette smoking, smoking cessation, and diabetes

There is evidence for increased risk of developing type 2 diabetes among cigarette smokers. In addition, smoking-associated health risks can exacerbate major conditions that precede or accompany diabetes, such as cardiovascular and kidney diseases. Smoking cessation can result in weight gain and a short-term worsening of some diabetic symptoms that may deter smokers with diabetes from attempting to quit. Additionally, there is limited evidence regarding the efficacy/safety of smoking cessation pharmacotherapies in this population and the general effects of smoking cessation, particularly for type 1 diabetes. Smoking cessation in diabetes therefore remains a highly relevant subject for further research.

Physical activity is negatively associated with the metabolic syndrome in the elderly

BACKGROUND

An inverse association between physical activity and metabolic syndrome has been reported in several cohorts, but very few specific studies are available in the elderly, in whom neurological and musculo-skeletal diseases are expected to lead to a remarkable age-related decline of physical activity.

AIM AND DESIGN

The relationships among physical activity, insulin resistance and metabolic syndrome were assessed in a cross-sectional study concerning 1144 subjects aged 65-91 years resident in Pianoro (northern Italy). Household and leisure-time activities were assessed by a self-administered questionnaire (Physical Activity Scale for Elderly--PASE). Routine clinical and biochemical data (including fasting insulin) were used to assess insulin resistance [Homeostasis Model Assessment (HOMA) method] and the prevalence of metabolic syndrome.

RESULTS

All PASE scores were inversely correlated with waist circumference, triglycerides and HOMA index, with highest significance for leisure-time activities (P < or = 0.005). The PASE score for household activities was also correlated inversely with blood glucose (P < 0.05), and directly with HDL cholesterol (P < 0.001). In logistic regression analysis, the metabolic syndrome was more prevalent among sedentary subjects (corresponding to the low tertile of leisure-time activities) than in the remaining more active population (odds ratio 1.51, 95% confidence interval 1.12-2.03, P = 0.007), independently of possible confounders.

CONCLUSION

Physical activity is inversely associated with insulin resistance and the metabolic syndrome even in the elderly. Community programs favoring physical activity are expected to significantly improve the health status in these subjects.

Women's health and the metabolic syndrome

The metabolic syndrome is a cluster of cardiovascular risk factors that identifies individuals at a relatively high, long-term risk for atherosclerosis, cardiovascular disease, and type 2 diabetes. Insulin resistance and central obesity are the main risk conditions underlying the metabolic syndrome. As obesity rates increase worldwide especially in women, accompanying rising frequency of insulin resistance, dyslipidemia, diabetes, and hypertension contribute to increasing rates of cardiovascular morbidity and mortality. According to the latest NCEP/ATPIII definition of the metabolic syndrome almost 25% (from 6.7 up to 43.5% according to age) of the United States and European adult population appear to have the syndrome and in the recent years it has been more prevalent in men than in women. Prevalence is increasing and the increase seems to be steeper in women. The contribution of the different components of the syndrome differs between genders. Age, endocrine dysfunction (especially loss of ovarian estrogens) as well as genetic factors modify the response to underlying factors. Physical inactivity, which diminishes by age, is more prevalent in women than in men. Treatment goals are to prevent cardiovascular disease by both altering the risk factors that are components of the syndrome and more importantly applying lifestyle modifications with caloric restriction and exercise.