Overview
Specific Aims
Importance
Background
Prelim. Studies

Methods
Study Design
Hypotheses
Study Pop.
Study Site
Size/Power
Limitations
Protocol
Data Collection
Analysis

Data
Introduction
Basic Data Sets
Variables Defs.
Codebook

Results
Working Papers
Publications
References

Introduction

To date, despite a number of studies describing the phenomenon of seasonal variation of cholesterol levels and discussing the implications of this phenomenon, there has been no study that has followed a cohort of individuals and obtained serial individual data on both lipid levels and those factors thought to be possibly causally related. This study fills this need, and is designed to produce a rich dataset that will provide the best-possible assessment of diet, physical activity and a number of other important parameters.

Overall study plan

A cohort of individuals recruited from the patient population of the Fallon clinic will be followed prospectively for one year. Baseline and serial measures taken quarterly for one year will be carried out. The quarterly interval was chosen because: of our experience in the WATCH which shows a gradual change in cholesterol levels across the seasons; the relatively short period of time required (~6 weeks) for cholesterol levels to respond to environmental stimuli,(54, 55). and the importance of the "off seasons" (i.e., fall and spring) as correlates of health-related behavior change (29). These serial measures will include: serum lipids and lipoproteins; platelets and hemostatic factors; weight, waist-hip ratio, height, BMI and blood pressure; dietary intake; physical activity; light exposure; and psychologic factors. Meteorologic data also will be collected. Data will be collected by written questionnaire and by the use of computer-assisted (evening) telephone 24 hour recalls (CATI), which will be used for the collection of dietary, physical activity and individual light-exposure data.