1. Read the paper by Must, et al (1992): Long-term morbidity and mortality of overweight adolescents. NEJM, 327:1350-55.
Questions Based on the table and formulas below, calculate, label AND state the meaning of your answer (interpret) in a sentence:
Status as Adolescents
Number of Participants
CHD Deaths
Person-years of observation
Overweight
238
40
9,329
Not overweight
270
30
10,980
Risk Ratio = a/(a + b)
c/(c + d)
AR%= (Incidence in exposed – Incidence in unexposed) x 100
Incidence in exposed
1. Complete the 2×2 table based on the information above: (4 points)
Status as Adolescents
CHD Deaths
Alive
Total
Overweight
a
b
238
Not overweight
c
d
270
Total
a+c
b+d
508
a =
b =
c =
d =
a+c =
b+d =
a) The risk of coronary heart disease (CHD) death in participants who were overweight as adolescents and in participants who were not. (8 points)
b) The risk ratio of CHD death associated with having been overweight in adolescence. (4 points)
c) The attributable risk percent for having been overweight in adolescence. Attributable risk estimates the amount or proportion of disease (here: death) that can be attributed to a specific exposure. (4 points)
d) The rate ratio of CHD death for individuals overweight at adolescence compared to lean adolescents. (4 points)
e) The risk difference of CHD death comparing overweight and lean adolescents. (4 points)
2. Based on your calculations, what can you conclude about the effect of being overweight during adolescence on the future risk of coronary heart disease? Decide whether this should be interpreted as “risk of death”. (2 points)
3. Now turn to the Must et al., paper.
a) Compare the crude RR of all-cause mortality associated with overweight in adolescence between men and women in Table 2. What do you conclude? (2 points)
b) Do you think it would be appropriate to show an overall RR of mortality associated with obesity, combining men and women?Explain why or why not. (3 points)