Insulin resistance and adipose-derived hormones in young men with untreated obstructive sleep apnea.

PURPOSE: Obstructive sleep apnea (OSA) increases the risk for insulin resistance (IR). The mechanisms that link the two are not clear and are frequently confounded by obesity. OSA is associated with alterations in adipose-derived hormones (adipokines) that increase IR; however, previous studies have focused on middle-aged and older adults. The objective of this study was to determine if IR and alterations in adipokines exist in young men with OSA, independent of obesity. METHODS: Subjects were assigned into the following groups based on body mass index and presence of OSA: obese with OSA (OSA, n = 12), obese without OSA (NOSA, n = 18), and normal weight without OSA (CON, n = 15). Fasting blood was obtained for batch analysis of biomarkers of IR. The homeostasis model assessment (HOMA) method was used to assess IR. RESULTS: HOMA and leptin were higher in the OSA group than the CON group. There were no differences in insulin, tumor necrosis factor alpha (TNF-α), and interleukin-6 (IL-6) between the OSA and NOSA groups. Adiponectin was lower in the OSA group vs. NOSA and CON; however, when controlled for central abdominal fat (CAF), the difference was nullified. When controlled for total body adiposity, however, CAF was 24 % higher in the subjects with OSA vs. subjects without OSA. CONCLUSIONS: These findings suggest that excess CAF in young men with OSA may contribute to risk for type 2 diabetes indirectly by a degree that would otherwise not be reached through obesity, although further research is needed.

Eating restraint is negatively associated with biomarkers of bone turnover but not measurements of bone mineral density in young women.

Relationships among bone mineral density (BMD), bone turnover markers, cortisol, calcium and vitamin D intakes, and cognitive eating restraint score were examined. Sixty-five healthy women, ages 18 to 25 years, had total body, spine, hip, and forearm BMD measured by dual-energy x-ray absorptiometry. Serum osteocalcin, urinary cross-linked N-telopeptide of type I collagen (NTx), and salivary cortisol were measured, and intakes of calcium and vitamin D were estimated from questionnaires. Cognitive eating restraint scores were determined from the Eating Inventory. Associations between measures were analyzed by Pearson correlations; predictors of BMD and bone turnover markers were tested using stepwise regression. Serum osteocalcin (P<0.01) and urinary NTx (P<0.05) were negatively related to cognitive eating restraint score. Intakes of calcium (P<0.05) and vitamin D (P<0.05) were associated with forearm BMD. Regression analyses indicated that vitamin D intake predicted total body (P<0.08) and forearm (P<0.01) BMD. Negative associations between cognitive eating restraint score and bone biomarkers suggest a reduction in bone remodeling, not reflected in current BMD.

Bone mineral density in postmenopausal women: does exercise training make a difference?

Although postmenopausal women are encouraged to exercise to preserve bone mineral density (BMD), few studies have looked at what type of exercise is most effective.

Cortisol, alpha amylase, and daily stressors in spouses of persons with mild cognitive impairment.

This study examines the effects of daily primary objective stressors (behavioral problems exhibited by persons with mild cognitive impairment) and subjective stressors (unpleasant marital interactions) on the diurnal cortisol pattern and the diurnal pattern of salivary alpha-amylase (sAA) of spousal care partners. Thirty spouse care partners (age 59-85 years) participated in a 7-day diary study and submitted saliva samples on 4 consecutive study days, totaling 406 valid samples. Results from multilevel models revealed that daily objective stressors were associated with elevated cortisol levels and a flatter slope but were not associated with sAA activity. Conversely, unpleasant marital interactions were associated with flatter sAA slopes but not associated with cortisol activity. Furthermore, daily levels of sAA moderated variations in cortisol in the presence of a primary objective stressor. The utility of our research has implications for advancing scientific understanding of biosocial processes and the development of stress prevention and intervention strategies.

Effects of daily stressors on the psychological and biological well-being of spouses of persons with mild cognitive impairment.

OBJECTIVES: This research documents spousal accounts of daily symptoms and behaviors of their husbands or wives with mild cognitive impairment (MCI) and assesses how MCI-related symptoms and care needs are associated with spouse care partners' psychological well-being and biomarkers of physiological wear and tear. METHOD: Thirty spouse care partners participated in a 7-day diary study and reported on behavior problems associated with MCI as well as daily stressors and strains they experienced. They also provided saliva samples on 4 of the study days. RESULTS: Multilevel models revealed daily variability and change in psychological affect and the diurnal cortisol rhythm. Daily primary stressors, everyday secondary strains, and marital interactions predicted these changes. DISCUSSION: The findings document the negative physiological effects of having a spouse with MCI and provide new details on probable causes of psychological and biological distress. They shed light on MCI-specific interventions to address couples' needs before severe disease progression occurs that could interfere with spouses' ability to provide home-based care and support.

Early evidence of increased risk for metabolic syndrome in young men with latent obstructive sleep apnea.

BACKGROUND: Obstructive sleep apnea (OSA) is characterized by a repetitive collapse of the upper airway during sleep and may affect as many as 1 in 5 adults. Although OSA appears to increase risk for metabolic syndrome in middle-aged adults, no data currently exist in a younger, preclinical cohort. METHODS: Forty-five sedentary young men: 12 overweight with OSA (OSA), 18 overweight without OSA (NOSA), and 15 normal-weight without OSA (CON). Respiratory distress index (RDI) was determined using an at-home, unsupervised, portable polygraphy device. Total and subcutaneous abdominal fat (SAF) were quantified using dual-energy X-ray absorptiometry (DXA). Blood pressure was obtained manually via auscultation. Fasting triglycerides, glucose, and high-density lipoprotein cholesterol (HDL-C) concentrations were analyzed from whole blood using a commercial lipid profile kit. RESULTS: The OSA group had 25% more SAF than the NOSA group (P < 0.05) and higher triglycerides (136.7 +/- 21.3 mg/dL versus 92.2 +/- 7.5, P < 0.05). RDI was directly related to fasting triglycerides (R = 0.32, P < 0.05) after controlling for SAF. The number of metabolic syndrome components was directly correlated to indices of adiposity, but not RDI. Using multiple linear regression analysis, triglycerides were the only independent predictor of RDI. CONCLUSIONS: Results from this study demonstrate that unique physiologic and anthropometric abnormalities exist in young men with occult OSA, beyond those that are seen in uncomplicated obesity. These findings may indicate early pathogenesis of metabolic syndrome in these young men.

Effect of post-exercise supplement consumption on adaptations to resistance training.

OBJECTIVE: Athletes are interested in nutritional manipulations that may enhance lean tissue gains stimulated by resistance training. Some research demonstrates that acute consumption of food containing protein causes superior muscle protein synthesis compared to isoenergetic foods without protein. This benefit has not been verified in longer-term training studies. We compared body composition and muscle function responses to resistance training in males who consumed a carbohydrate or a multi-macronutrient beverage following each training session. METHODS: Nineteen, untrained men (18-25 years) consumed either a milk (MILK) or a carbohydrate-electrolyte (CHO) drink immediately following each workout during a 10 week resistance training program. Muscle strength (1RM for seven exercises), body composition (DXA scan), fasted, resting concentrations of serum total and free testosterone, cortisol, IGF-1, and resting energy expenditure (REE) were measured prior to and at the end of training. RESULTS: Resistance training caused an increase (44 +/- 4%, p < 0.001) in muscular strength for all subjects. The training program reduced percent body fat (8%, p < 0.05, -0.9 +/- 0.5 kg) and increased fat-free soft tissue (FFST) mass (2%, 1.2 +/- 0.3 kg, p < 0.01). MILK tended to increase body weight and FFST mass (p = 0.10 and p = 0.13, respectively) compared to CHO. Resting total and free testosterone concentrations decreased from baseline values in all subjects (16.7%, 11%, respectively, p < 0.05). Significant changes in fasting IGF-1, cortisol, and REE across training were not observed for either group. CONCLUSION: Post-resistance exercise consumption of MILK and CHO caused similar adaptations to resistance training. It is possible that a more prolonged training with supplementation period would expand the trend for greater FFST gains in MILK.