You are part of a team of researchers interested in the long-term effects of altitude change in human blood pressure. You travel to Kathmandu, Nepal (altitude: 1,336) to measure the blood pressure of a number of Sherpas native to Namche Bazaar (altitude: 3,446 m) in the Khumbu region at the foothills of Mount Everest. All Shepas have migrated to and settle in Kathmandu valley for more stable work. Previous research suggests that migration of this kind (high altitude to low altitude) might cause higher blood pressure at first, but over time (years since migration) blood pressure will decrease, and this effect may be modified by age.
A total of 39 Sherpa males, conveniently identified through a local trekking company, aged 21 years and above agreed to participate in the study. All were born and had lived in the Khumbu region of Nepal prior to migrating to Kathmandu. Physical measurements are listed below including the primary outcome, systolic blood pressure.
All measurements were taken 3 times and the values averaged to minimize measurement error. Analyses should address the following questions: Is there a relationship between systolic blood pressure and how long the Sherpas have lived in their new environment, the Kathmandu valley, after accounting for anthropometric differences? Does this effect vary by age?
Data file: fexamq3 (N= 39) Following are the list of variables: Age Age in years Years Years since migration Weight Weight (kilograms) Height Height (millimeters) Chin Chin skin fold (millimeters) Forearm Forearm skin fold (millimeters) Calf Calf skin fold (millimeters) Systol Systolic blood pressure (mm Hg) Since there are many predictors and few subjects you are advised to create composite indicators of obesity including body mass index (BMI) and skin fold thickness (SKT). In two to three paragraphs describe the data analysis plan and results with supporting information from the analysis. Evaluate and discuss the impact of selection bias, misclassification, and confounding on the results. BMI (kg/m2)= weight(kg)/height(m)2 SFT = sum the 3 skin fold measures