Transmission of second-hand smoke sensitivity and smoking attitude in a family

Genetic influences on the onset of obstructive sleep apnoea and daytime sleepiness: a twin study

Background

Obstructive sleep apnoea (OSA) is one of the major sources of the excessive daily sleepiness, cognitive dysfunction, and it increases cardiovascular morbidity and mortality. Previous studies suggested a possible genetic influence, based on questionnaires but no objective genetic study was conducted to understand the exact variance underpinned by genetic factors.

Methods

Seventy-one Hungarian twin pairs involved from the Hungarian Twin Registry (48 monozygotic, MZ and 23 dizygotic, DZ pairs, mean age 51 ± 15 years) underwent overnight polysomnography (Somnoscreen Plus Tele PSG, Somnomedics GMBH, Germany). Apnoea hypopnea index (AHI), respiratory disturbance index (RDI) and oxygen desaturation index (ODI) were registered. Daytime sleepiness was measured with the Epworth Sleepiness Scale (ESS). Bivariate heritability analysis was applied.

Results

The prevalence of OSA was 41% in our study population. The heritability of the AHI, ODI and RDI ranged between 69% and 83%, while the OSA, defined by an AHI ≥5/h, was itself 73% heritable. The unshared environmental component explained the rest of the variance between 17% and 31%. Daytime sleepiness was mostly determined by the environment, and the variance was influenced in 34% by the additive genetic factors. These associations were present after additional adjustment for body mass index.

Conclusion

OSA and the indices of OSA severity are heritable, while daytime sleepiness is mostly influenced by environmental factors. Further studies should elucidate whether close relatives of patients with OSA may benefit from early family risk based screening.

Factors Associated With Smoking Status among HIV-Positive Patients in Routine Clinical Care

BACKGROUND

Treatment-related reductions in morbidity and mortality among human immunodeficiency virus (HIV)-positive patients have been attenuated by cigarette smoking, which increases risk of cardiovascular, respiratory, and neoplastic diseases. This study investigated factors associated with smoking status among HIV-positive patients.

METHODS

This cross-sectional study included 2,464 HIV-positive patients attending the HIV Clinic at the University of Alabama at Birmingham between April 2008 and December 2013. Smoking status (current, former, never), psychosocial factors, and clinical characteristics were assessed. Multinomial logistic regression was used to obtain unadjusted and adjusted odds ratios (OR) and 95% confidence intervals (CI) for the association of the various factors with smoking status.

RESULTS

Among HIV-positive patients (mean age 45 years, 75% male, 55% African-American), the majority reported a history of smoking (39% current and 22% former smokers). In adjusted models, patient characteristics associated with increased odds of current smoking were male gender (OR for heterosexual men, 1.8 [95% CI: 1.3-2.6]; for men who have sex with men, 1.5 [1.1-1.9]), history of respiratory diseases (1.5 [1.2-1.9]), unsuppressed HIV viral load (>50 copies/mL) (1.5 [1.1-1.9]), depression (1.6 [1.3-2.0]), anxiety (1.6 [1.2-2.1]), and prior and current substance abuse (4.7 [3.6-6.1] and 8.3 [5.3-13.3] respectively). Male gender, anxiety, and substance abuse were also associated with being a former smoker.

CONCLUSIONS

Smoking was common among HIV-positive patients, with several psychosocial factors associated with current and former smoking. This suggests smoking cessation programs in HIV clinic settings may achieve greater impact by integrating interventions that also address illicit substance abuse and mental health.