The Obesity-Sexual Health Relationship
Source: Esposito K, et al. Obesity and sexual dysfunction, male and female. Int J Impot Res 2008;20:358-365.
The established causal relation ship between endothelial dysfunction and erectile dysfunction (ED) provides mechanistic insight into an obesity-sexual health linkage. Obesity is associated with an increased incidence of diabetes, dyslipidemia, and hypertension, all of which contribute to endothelial dysfunction. Both the 9-year follow up of the Massachusetts Male Aging Study and the 25-year follow up of the Rancho Bernardo Study found overweight to be an independent risk factor for ED, essentially doubling the odds ratio. Although correlation with BMI is strong, it appears to be central adiposity (aka visceral adiposity) that is most strongly related to endothelial dysfunction.
The relationship between obesity in women and sexual health is both less well studied, and not as easily explained. Available data suggest that disorders of arousal, lubrication, and orgasm are more common in overweight and obese women, although sexual desire disorders (e.g., hypoactive sexual desire disorder) and sexual pain disorders (e.g., dyspareunia) are not. In contrast to men, in whom body fat distribution is relevant, it is BMI alone which shows best correlation in women. Interestingly, scores on the Female Sexual Function Index (FSFI) correlate with BMI in women with prevalent sexual dysfunction, but do not show this same correlation in unselected healthy populations.
Women with metabolic syndrome score lower on the FSFI than matched controls, although a plausible putative relationship remains to be established.
Interventions targeting weight reduction have been promising: An exercise/diet program in men has been shown to improve erectile function, and a 2-year study of the Mediterranean diet in women improved FSFI scores. Improved sexual health may be another reason to advocate healthful diet and exercise for our patients.
Body Composition and Treatment of Hypogonadism
Source: Svartberg J, et al. Testosterone treatment in elderly men with subnormal testosterone levels improves body composition and BMD in the hip. Int J Impot Res 2008;20:378-387.
The tromso study is an ongoing health survey of men who live in the municipality of Tromso, Norway. In 2001, men aged 60-80 years (n=335) with hypogonadism (HGO) were identified and matched with eugonadal age-matched controls; in 2005, these hypogonadal men were enrolled in a 1-year testosterone treatment intervention.
At baseline, HGO subjects had a greater percentage of fat mass, including visceral, subcutaneous, and total fat mass, than their matched controls. Fasting glucose, 2-hour glucose levels, and triglycerides were also higher in the HGO group, reflecting a correspondingly higher level of insulin resistance.
The testosterone treatment intervention was carried out in 69 men of the HGO group. Treatment produced an increase in fat-free mass, a decrease in fat mass, and a decrease specifically in total abdominal adipose tissue. As in prior trials, testosterone replacement increased bone mineral density, predominantly in the hip. Metabolic defects seen in HGO were not corrected by testosterone replacement. Testosterone replacement has numerous favorable effects on body composition in hypogonadal men.
Changing Metrics for Diabetes Management
Source: Nathan DM, et al. Translating the A1C assay into estimated average glucose values. Diabetes Care 2008;31:1473-1478.
The conceptualization of hemoglobin A1c levels (A1c) as a marker of adequacy of diabetes control has remained elusive for many of our patients. Since blood glucose is measured typically (in the United States) in mg%, and numbers typically range from 100 and higher, the concept that an A1c of 7.0 somehow corresponds to good glucose control is not surprisingly an item of potential disconnect.
Nathan et al performed an international multicenter study utilizing the combination of continuous glucose monitoring with A1c levels in subjects (n=507) with type 1 diabetes, type 2 diabetes, and non-diabetics.
Subjects underwent continuous glucose monitoring with a Medtronic device that performs serum glucose determinations every 5 minutes. This was performed for 2 days at baseline, then every 4 weeks for 12 weeks. At the same time, subjects performed an 8-point fingerstick glucose panel. All told, each subject completed approximately 2700 glucose readings during the 3-month period.
The linear regression relationship between A1c and average glucose was established to be the same in both normal and diabetic individuals. An A1c of 7 correlates with an average glucose of 154 mg%. For each incremental increase of 1 unit in A1c, average glucose increased by approximately 30 mg%. Adoption of the average glucose metric might simplify our patients' understanding of goals in diabetes.
Which Is Best for Weight Loss: Low Carb, Low Fat, or Mediterranean?
Source: Shai I, et al. Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet. N Engl J Med 2008;359:229-241.
In overweight individuals, the single most critical marker of success is simply reduction of weight. On the other hand, proponents of diets that specifically target individual dietary components, such as carbohydrate or fat, point to putative benefits of specific restrictions. If weight loss is the ultimate arbiter of success, it remains unclear which dietary plan is the best. To date, the best evidence for endpoint reduction resides with the Mediterranean diet in secondary prevention of cardiovascular events: A greater than 70% relative risk reduction has been demonstrated (superior, literally, to that obtained with statins in a similar setting).
A two-year trial randomized obese (BMI = 31 kg/m2) subjects to either a fat-restricted, carbohydrate-restricted, or Mediterranean diet. Patients received intensive instruction from dietitians. The low-fat and Mediterranean diets each provided 1500 kcal/d (women) or 1800 kcal/d (men). The low-carbohydrate diet did not have an absolute calorie limit; instead, subjects were restricted to a maximum intake of 120 g/d carbohydrate.
At two years, the low-carbohydrate and Mediterranean diets produced a 5.5 kg and 4.6 kg weight loss, respectively. The low-fat diet resulted on a 2.9 kg weight loss. The authors suggest that either of the two more successful diets might be appropriate; since the Mediterranean diet provided better glycemic control, and the low-carbohydrate diet resulted in better lipid effects, individual choice of diet could be informed by baseline risk factors.
Influenza Vaccine Efficacy in Senior Citizens
Source: Jackson ML, et al. Influenza vaccination and risk of community-acquired pneumonia in immunocompetent elderly people: A population-based, nested case-control study. Lancet 2008;372:398-405.
Influenza vaccination (FLUVax) is multi-intentioned: reduction in incidence of influenza, reduction of influenza-related morbidities (e.g., pneumonia, heart failure), reduction of transmission to others, and ultimately, since influenza-related deaths number more than 15,000 every year, reduction in mortality. Even though most clinicians consider the value of FLUVax to be a given, controversy still exists about the relative merits of FLUVax.
The study population addressed in the communication by Jackson et al is composed of immunocompetent community-dwelling elders age 65-94 years in Washington state (n=53,929). Persons who had a history of cancer, chronic renal disease, or prescriptions for immunosuppressive medications were excluded (as non-immunocompetent). The object of the study was to discern whether FLUVax reduced cases of community acquired pneumonia (CAP) in vaccinated groups. Extensive evaluation of both recorded diagnoses, as well as review of chest X-rays to confirm the presence of pneumonia in both inpatients and outpatients, strengthened the accuracy of pneumonia diagnosis.
During the influenza season of three consecutive years (2001-2003), the odds ratio for pneumonia among vaccinated versus non-vaccinated individuals was 1.04 (i.e., a slightly greater, though not statistically significant, increased risk). These data do not confirm a statistically significant reduction in pneumonia in immunocompetent senior citizens through influenza vaccine.
Best Combination Therapy for Symptomatic Relief in COPD
Source: Rabe KF, et al. Comparison of a combination of tiotropium plus formoterol to salmeterol plus fluticasone in moderate COPD. Chest 2008;134:255-262.
There are no disease-modifying pharmacotherapies for COPD. That is, although bronchodilators, anticholinergic agents, and inhaled corticosteroids improve FEV1 and reduce symptoms, decline in pulmonary function continues unabated and lung function returns promptly once medication is stopped.
Overall, in COPD anticholinergic therapy (e.g., ipratropium, tiotropium) provides greater improvements in pulmonary function than beta-adrenergic therapy or inhaled corticosteroids. Combination therapy (anticholinergic + beta agonist or beta agonist + inhaled steroid) is more effective than either monotherapy. Which combination therapy is to be preferred has not yet been established.
Patients with moderate COPD were randomized to receive 6 weeks of either tiotropium + formoterol or salmeterol + fluticasone. At the end of this time period, an assessment of lung function over a 12-hour period was performed. The endpoint was the area-under-the-curve of pulmonary function for 12 hours at end of study.
The tiotropium + formoterol combination was statistically significantly superior to the salmeterol + fluticasone combination; for instance, the mean difference in FEV1 was 78 mL (p = 0.0006). Need for use of rescue medications was the same for both groups.
At least over the short term, the bronchodilator combination of tiotropium + formoterol provides superior improvements in bronchodilation compared to salmeterol + fluticasone.
The Obesity-Sexual Health Relationship; Body Composition and Treatment of Hypogonadism; Changing Metrics for Diabetes Management; Which Is Best for Weight Loss: Low Carb, Low Fat, or Mediterranean?; Influenza Vaccine Efficacy in Senior Citizens; Best Combination Therapy for Symptomatic Relief in COPDYou have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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