High long-term cortisol levels, measured in scalp hair, are associated with a history of cardiovascular disease.

"Abstract

BACKGROUND:

Stress is associated with an increased incidence of cardiovascular disease. The impact of chronic stress on cardiovascular risk has been studied by measuring cortisol in serum and saliva, which are measurements of only 1 time point. These studies yielded inconclusive results. The measurement of cortisol in scalp hair is a novel method that provides the opportunity to measure long-term cortisol exposure. Our aim was to study whether long-term cortisol levels, measured in scalp hair, are associated with cardiovascular diseases.

METHODS:

A group of 283 community-dwelling elderly participants were randomly selected from a large population-based cohort study (median age, 75 y; range, 65-85 y). Cortisol was measured in 3-cm hair segments, corresponding roughly with a period of 3 months. Self-reported data concerning coronary heart disease, stroke, peripheral arterial disease, diabetes mellitus, and other chronic noncardiovascular diseases were collected.

RESULTS:

Hair cortisol levels were significantly lower in women than in men (21.0 vs 26.3 pg/mg hair; P < .001). High hair cortisol levels were associated with an increased cardiovascular risk (odds ratio, 2.7; P = .01) and an increased risk of type 2 diabetes mellitus (odds ratio, 3.2; P = .04). There were no associations between hair cortisol levels and noncardiovascular diseases.

CONCLUSIONS:

Elevated long-term cortisol levels are associated with a history of cardiovascular disease. The increased cardiovascular risk we found is equivalent to the effect of traditional cardiovascular risk factors, suggesting that long-term elevated cortisol may be an important cardiovascular risk factor."

http://www.ncbi.nlm.nih.gov/pubmed/23596141

Effects of dietary composition on energy expenditure during weight-loss maintenance

"Abstract

CONTEXT:

Reduced energy expenditure following weight loss is thought to contribute to weight gain. However, the effect of dietary composition on energy expenditure during weight-loss maintenance has not been studied.

OBJECTIVE:

To examine the effects of 3 diets differing widely in macronutrient composition and glycemic load on energy expenditure following weight loss.

DESIGN, SETTING, AND PARTICIPANTS:

A controlled 3-way crossover design involving 21 overweight and obese young adults conducted at Children's Hospital Boston and Brigham and Women's Hospital, Boston, Massachusetts, between June 16, 2006, and June 21, 2010, with recruitment by newspaper advertisements and postings.

INTERVENTION:

After achieving 10% to 15% weight loss while consuming a run-in diet, participants consumed an isocaloric low-fat diet (60% of energy from carbohydrate, 20% from fat, 20% from protein; high glycemic load), low-glycemic index diet (40% from carbohydrate, 40% from fat, and 20% from protein; moderate glycemic load), and very low-carbohydrate diet (10% from carbohydrate, 60% from fat, and 30% from protein; low glycemic load) in random order, each for 4 weeks.

MAIN OUTCOME MEASURES:

Primary outcome was resting energy expenditure (REE), with secondary outcomes of total energy expenditure (TEE), hormone levels, and metabolic syndrome components.

RESULTS:

Compared with the pre-weight-loss baseline, the decrease in REE was greatest with the low-fat diet (mean [95% CI], -205 [-265 to -144] kcal/d), intermediate with the low-glycemic index diet (-166 [-227 to -106] kcal/d), and least with the very low-carbohydrate diet (-138 [-198 to -77] kcal/d; overall P = .03; P for trend by glycemic load = .009). The decrease in TEE showed a similar pattern (mean [95% CI], -423 [-606 to -239] kcal/d; -297 [-479 to -115] kcal/d; and -97 [-281 to 86] kcal/d, respectively; overall P = .003; P for trend by glycemic load < .001). Hormone levels and metabolic syndrome components also varied during weight maintenance by diet (leptin, P < .001; 24-hour urinary cortisol, P = .005; indexes of peripheral [P = .02] and hepatic [P = .03] insulin sensitivity; high-density lipoprotein [HDL] cholesterol, P < .001; non-HDL cholesterol, P < .001; triglycerides, P < .001; plasminogen activator inhibitor 1, P for trend = .04; and C-reactive protein, P for trend = .05), but no consistent favorable pattern emerged.

CONCLUSION:

Among overweight and obese young adults compared with pre-weight-loss energy expenditure, isocaloric feeding following 10% to 15% weight loss resulted in decreases in REE and TEE that were greatest with the low-fat diet, intermediate with the low-glycemic index diet, and least with the very low-carbohydrate diet.

TRIAL REGISTRATION:

clinicaltrials.gov Identifier: NCT00315354."

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