Question

A 2012 article in the New England Journal reports the results of a randomized trial to assess the association between regular usage of asthma medication prior to turning 18 years old, and height at age 18 years. As per the authors,

“From December 1993 through September 1995,we randomly assigned 1041 children between the ages of 5 and 13 years with mild-to-moderate asthma to one of three study groups in the double-blind, placebo-controlled CAMP trial.”

(reference: Kelly H, et al. Effect of Inhaled Glucocorticoids in Childhood on Adult Height. New England of Medicine (2012). 367 (10))

The random assignment groups were Budesonide, Nedocromil and placebo. The following graphic shows the distribution of female and male participant heights at different times in the study follow-up, presented for the Budesonide and placebo samples.

Budesonide Placebo A Unadjusted Height Distribution 200 190- 180- 170- 160- H Height (cm) 0 000 120- 110. Trial entry 2 Yr Adult Trial entry 2 Yr Trial end Adult T rial end Females Males

Which of the following best describes the height variability patterns for males and females in this study?

1. The height values are less variable for both female and male adults, as compared to their younger selves in the prior 3 measurement periods.
2. Variability in the height values systematically increases for male heights across the follow-up period, and systematically decreases for females during the same time-period.
3. The height values are more variable for both female and male adults, as compared to their younger selves in the prior 3 measurement periods.
4. Variability in the height values systematically decreases for male heights across the follow-up period, and systematically increases for females during the same time-period.

Answer 1

The height values are less variable for both female and male adults, as compared to their younger selves in the prior 3 measurement periods.

Option A is correct.