Habitual sleep/wake patterns in the Old Order Amish: heritability and association with non-genetic factors.

STUDY OBJECTIVES: We sought to evaluate the contribution of genetic and non-genetic factors on habitual sleep/wake patterns in a community-dwelling agrarian population using a physical activity monitoring device, the Actical. DESIGN: Cross-sectional population-based study of healthy Old Order Amish enrolled in the Heredity and Phenotype Intervention (HAPI) Heart Study. SETTING: Lancaster County, PA, USA. PARTICIPANTS: 723 healthy adults (54% men) with a mean age of 43.3 ± 13.8 years (range: 20-80). 96% of the subjects were connected into one 5-generation pedigree. INTERVENTIONS: N/A. MEASUREMENTS: Participants wore Actical accelerometers 24 hours/day for 7 days to determine physical activity level, as well as habitual wake time, bedtime, and sleep duration. Participants completed the Horne-Östberg Morningness-Eveningness Questionnaire (MEQ), a modified Epworth Sleepiness Scale (ESS), and a lifestyle questionnaire. A sub-study of 164 participants kept sleep diaries. RESULTS: Habitual wake time and bedtime determined by Actical were highly correlated with results from sleep diaries (r = 0.82 for wake time and 0.72 for bedtime, both P < 0.0001). After adjustment for age, sex, occupation, and season, higher activity level was associated with earlier wake time but not with bedtime, and correspondingly with shorter sleep duration. After adjustment for the aforementioned factors and the effects of a shared household, habitual wake time, MEQ score, and ESS score showed significant heritability (wake time h(2) = 0.20, MEQ h(2) = 0.21, and ESS h(2) = 0.17). CONCLUSIONS: Objectively measured wake time, self-reported morningness-eveningness preference, and daytime sleepiness appear heritable and wake time may be associated with physical activity level.

Improving diagnosis of central venous catheter-related bloodstream infection by using differential time to positivity as a hospital-wide approach at a cancer hospital.

OBJECTIVES: Considering the difficulty of diagnosing catheter-related bloodstream infection (CRBSI), Koo Foundation Sun Yat-Sen Cancer Center uses differential time to positivity (DTP) as a hospital-wide approach to improve the diagnosis of CRBSI in febrile patients with indwelling central venous catheters (CVCs). This study describes the result of a hospital-wide use of DTP in a real practice setting. METHODS: During January 2003-August 2007, 142 positive paired blood cultures from 125 patients without infection focus other than CVC were included. These were evaluated by DTP and semi-quantitative catheter culture (SQCC) to confirm the diagnosis of CRBSI, and were further divided into two groups: confirmed (either by DTP or SQCC) and non-confirmed CRBSI (neither DTP nor SQCC positive). RESULTS: Fifty-nine point two percent (84/142) of episodes were confirmed as CRBSI, of which DTP was positive in 83.3% (n=70). Non-confirmed CRBSI was associated with hematologic malignancy, neutropenia status, previous antibiotics exposure and a lower CVC removal rate. CONCLUSIONS: A hospital-wide approach of DTP was practical and feasible in improving the diagnosis of CRBSI in a real practice setting.

Association between telomere length, specific causes of death, and years of healthy life in health, aging, and body composition, a population-based cohort study.

Although telomere length (TL) is known to play a critical role in cellular senescence, the relationship of TL to aging and longevity in humans is not well understood. In a large biracial population-based cohort, we tested the hypotheses that elderly persons with shorter TL in peripheral white blood cells have poorer survival, shorter life span, and fewer years of healthy life (YHL). Associations were evaluated using Cox proportional hazard models and linear regression analyses where appropriate. TL (in kilo base pairs) was not associated with overall survival (hazard ratio 1.0; 95% confidence interval 0.9-1.1) or death from any specific underlying cause including infectious diseases, cancer, or cardiac and cerebrovascular diseases. TL, however, was positively associated with more YHL (beta = 0.08 +/- 0.04, p = .03). Findings suggest that TL may not be a strong biomarker of survival in older individuals, but it may be an informative biomarker of healthy aging.

Telomere length is paternally inherited and is associated with parental lifespan.

Telomere length (TL) is emerging as a biomarker for aging and survival. To evaluate factors influencing this trait, we measured TL in a large homogeneous population, estimated the heritability (h(2)), and tested for parental effects on TL variation. Our sample included 356 men and 551 women, aged 18-92 years, from large Amish families. Mean TL in leukocytes was measured by quantitative PCR (mean: 6,198 +/- 1,696 bp). The h(2) of TL was 0.44 +/- 0.06 (P < 0.001), after adjusting for age, sex, and TL assay batch. As expected, TL was negatively correlated with age (r = -0.40; P < 0.001). There was no significant difference in TL between men and women, consistent with our previous findings that Amish men lived as long as Amish women. There was a stronger and positive correlation and association between TL in the offspring and paternal TL (r = 0.46, P < 0.001; beta = 0.22, P = 0.006) than offspring and maternal TL (r = 0.18, P = 0.04; beta = -0.02, P = 0.4). Furthermore, we observed a positive correlation and association between daughter's TL and paternal lifespan (r = 0.20, P < 0.001; beta = 0.21, P = 0.04), but not between daughter's TL and maternal lifespan (r = -0.01, beta = 0.04; both P = not significant). Our data, which are based on one of the largest family studies of human TL, support a link between TL and aging and lifespan and suggest a strong genetic influence, possibly via an imprinting mechanism, on TL regulation.