Epidemiologic and public health researchers frequently include several dependent variables, repeated assessments, or subgroup analyses in their investigations. These factors result in multiple tests of statistical significance and may produce type 1 experimental errors. This study examined the type 1 error rate in a sample of public health and epidemiologic research. A total of 173 articles cho...

BACKGROUND Teenage motherhood is strongly associated with a range of disadvantages for both the mother and the child. No epidemiological studies have examined related factors for teenage motherhood at both area and individual levels among Japanese women. Therefore, we performed a multilevel analysis of nationwide data in Japan to explore the association of area- and individual-level factors wit...

STUDY OBJECTIVES The goal of this study was to examine whether there were ethnic differences in polysomnographically recorded sleep, either in the controlled laboratory environment or in the home setting. DESIGN Prospective study of ethnic differences in stress physiology and sleep. SETTING Two sleep recordings were performed on consecutive nights in a hospital-based sleep laboratory, follo...

What generates health? What makes us move in the direction of health? These simple and original questions created an opening to a new way of thinking in health research. It was raised in the late 1970ies by Aaron Antonovsky, a medical sociologists interested in stress theory who had undertaken a traditional epidemiological study on the effects of menopause on women who had undergone extremely s...

background: musculoskeletal disorders (msds) are common among employees throughout the world, particularly in high risk groups such as nurses. objective: to determine the prevalence of msds among nurses in a large hospital in ahwaz, southwestern iran, and to examine its correlation with gender, age, shift working, years at service and smoking. methods: using a self-reported questionnaire-based ...

What is the distribution and population density of ticks transmitting the Lyme spirochete? Data on tick distribution are scarce. Ixodes dammini appears to be limited to sea-level ecosystems, whereas L pacificus populations are adequate up to 7,000 feet elevation. Three cases of Lyme disease had their exposure above 5,000 feet in the Sierras of northern California. The nymphal tick is very small...

This review basically provided a conceptual framework for sample size calculation in epidemiologic studies with various designs and outcomes. The formula requirement of sample size was drawn based on statistical principles for both descriptive and comparative studies. The required sample size was estimated and presented graphically with different effect sizes and power of statistical test at 95...