Clinical Briefs

By Louis Kuritzky, MD, Clinical Assistant Professor, University of Florida, Gainesville. Dr. Kuritzky is a consultant for GlaxoSmithKline and is on the speaker's bureau of GlaxoSmithKline, 3M, Wyeth-Ayerst, Pfizer, Novartis, Bristol-Myers Squibb, AstraZeneca, Jones Pharma, and Boehringer Ingelheim.

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 relationship 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 nine-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 two-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.

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 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 vs 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.

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 two days at baseline, then every four 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 three-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.