Power analysis for cross-sectional and longitudinal study designs

Predictors of Abnormal Sleep Duration in Older Adults With Hip Fracture and Diabetes

BACKGROUND

Abnormal sleep duration affects recovery in older adults with hip fracture and diabetes mellitus (DM) negatively. However, the predictors of abnormal sleep duration in this population remain unknown.

PURPOSE

This study was designed to explore the predictors of abnormal sleep duration among older adults with hip fracture and DM within 6 months of hospital discharge.

METHODS

A longitudinal study using secondary data from a randomized controlled trial was implemented. Data on fracture-related factors (diagnosis, surgical methods) were collected from medical charts. Information on the duration of DM, methods of DM control, and diabetes-related peripheral vascular disease was collected by asking simple questions. Diabetic peripheral neuropathy was assessed using the Michigan Neuropathy Screening Instrument. Sleep duration outcomes were determined using data collected from a SenseWear armband.

RESULTS

Having more comorbidities (OR = 3.14, p = .04), having undergone open reduction (OR = 2.65, p = .005), having undergone closed reduction with internal fixation (OR = 1.39, p = .04), and having DM (OR = 1.18, p = .01), diabetic peripheral neuropathy (OR = 9.60, p = .02), or diabetic peripheral vascular disease for a longer duration (OR = 15.62, p = .006) were all associated with a higher risk of abnormal sleep duration.

CONCLUSIONS

The findings indicate that patients with more comorbidities or who had undergone internal fixation, had a long DM history, or had complications are more likely to have abnormal sleep duration. Thus, greater attention should be focused on the sleep duration of diabetic older adults with hip fracture who are affected by these factors to achieve better postoperative recovery.

Association between Asthma Control and Exposure to Greenness and Other Outdoor and Indoor Environmental Factors: A Longitudinal Study on a Cohort of Asthmatic Children

Achieving and maintaining asthma control (AC) is the main goal of asthma management. Indoor and outdoor environmental factors may play an important role on AC. The aim of this longitudinal study was to evaluate the association between AC and exposure to greenness and other outdoor or indoor environmental factors in a cohort of asthmatic children. This study involved 179 asthmatic children (5-16 years). Parents were interviewed through a modified version of the SIDRIA questionnaire. AC was assessed at each visit. Exposure to greenness was measured using the normalized difference vegetation index (NDVI). A logistic regression model was applied for assessing risk factors for uncontrolled asthma (UA). Low NDVI exposure was a risk factor for UA (OR: 2.662, 95% CI (1.043-6.799)); children exposed to passive smoke during pregnancy had a higher risk of UA than those non-exposed to passive smoke during pregnancy (OR: 3.816, 95% CI (1.114-13.064)); and a unit increase in the crowding index was associated with an increased risk of UA (OR: 3.376, 95% CI (1.294-8.808)). In conclusion, the current study provided a comprehensive assessment of urban-related environmental exposures on asthma control in children, using multiple indicators of greenness and other outdoor or indoor environmental factors.

Immune marker changes and risk of multiple myeloma: a nested case-control study using repeated pre-diagnostic blood samples

Biomarkers reliably predicting progression to multiple myeloma (MM) are lacking. Myeloma risk has been associated with low blood levels of monocyte chemotactic protein-3 (MCP-3), macrophage inflammatory protein-1 alpha (MIP-1α), vascular endothelial growth factor (VEGF), fibroblast growth factor-2 (FGF-2), fractalkine, and transforming growth factor-alpha (TGF-α). In this study, we aimed to replicate these findings and study the individual dynamics of each marker in a prospective longitudinal cohort, thereby examining their potential as markers of myeloma progression. For this purpose, we identified 65 myeloma cases and 65 matched cancer-free controls each with two donated blood samples within the Northern Sweden Health and Disease Study. The first and repeated samples from myeloma cases were donated at a median 13 and 4 years, respectively, before the myeloma was diagnosed. Known risk factors for progression were determined by protein-, and immunofixation electrophoresis, and free light chain assays. We observed lower levels of MCP-3, VEGF, FGF-2, and TGF-α in myeloma patients than in controls, consistent with previous data. We also observed that these markers decreased among future myeloma patients while remaining stable in controls. Decreasing trajectories were noted for TGF-α (P=2.5 × 10⁻⁴) indicating progression to MM. Investigating this, we found that low levels of TGF-α assessed at the time of the repeated sample were independently associated with risk of progression in a multivariable model (hazard ratio = 3.5; P=0.003). TGF-α can potentially improve early detection of MM.

Cigarette smoking in a Middle Eastern country and its association with hospitalisation use: a nationwide cross-sectional study

OBJECTIVES

Little is known about the distribution of cigarette smoking by place and persons at the national level or its burden on healthcare expenditure in countries of the Middle East. We examine in this study the pattern of cigarette smoking by age, gender and geography and assess its association with hospitalisation use in Lebanon, a small middle-income country in the Middle East.

DESIGN

Population-based cross-sectional study.

SETTING

The study draws on data collected as part of the nationwide multistage cluster sample Nutrition and Non-Communicable Disease Risk Factor survey conducted in Lebanon in 2009.

PARTICIPANTS

A total of 2836 Lebanese adults 18 years and over.

MEASURES

Hospitalisation, the outcome variable, was measured using one item and recoded as a dichotomous variable. Cigarette smoking, the main exposure variable, was assessed by examining smoking status and pack-years, capturing intensity, frequency and duration of exposure.

RESULTS

The overall prevalence rate of current smoking in this study was 34.7%, with significantly higher rates in males than females (42.9% and 27.5%, respectively). Close to two-thirds of the study population reported ever being hospitalised (62.8%). Compared to non-smokers, past and current smokers were significantly more likely to be hospitalised, after controlling for sociodemographic and health-related characteristics (OR=2.9, 95% CI 1.26 to 3.34, and OR=1.35, 95% CI 1.12 to 1.63, respectively). Hospitalisation use increased significantly in a dose-response manner with increasing pack-years.

CONCLUSIONS

When compared to regional and international estimates, the prevalence rates of smoking in Lebanon are considerably high, with percentages among women being among the highest in the region. Our findings of increased odds of hospitalisation among ever smokers, net of the effect of comorbidity, underscore the additional burden of smoking on the healthcare bill cost. Continued monitoring of smoking rates and disease surveillance frameworks are warranted in developing countries for policy development and evaluation.