13.122 Use polytomous logistic regression with group = 0 as the reference group to assess the association between SBP z-score group and the following variables:

(a) BMI,

(b) height, 

(c) region (i.e., Rhondda Fach vs. Vale of Glamorgan),

(d) occupation (treat occupation codes of 5€“9 as missing for this analysis). Of particular interest is the comparison of group = 2 vs. group = 0. 

Hypertension

The data set WALES.DAT contains familial data on blood pressure (bp) in two-communities in South Wales (the Rhondda Fach and the Vale of Glamorgan). Subjects were seen at 4 visits from the mid 1950s to the early 1960s. For this problem we will focus on bp among adults (age ‰¥ 30) at the first visit. To standardize bp for age and sex, we will use the z-score approach within 10-year age-sex groups (i.e., age 30€“39 males/40€“49 males/50€“59 males/60+ males/30€“39 females/40€“49 females/50€“59 females/60+ females) where

 

We then group SBP z-score for ease of interpretation as

follows:

SBP z-score group = 2 if SBP z-score ‰¥ 1.0,

= 1 if SBP z-score ‰¥ 0.5 and < 1.0,

= 0 if SBP z-score < 0.5 and not missing

Transcribed Image Text:

Systolic bp (SBP) z-score SBP - mean SBP within an age-sex group sd SBP within an age-sex group ||