TY - JOUR
T1 - Combining risk estimates from observational studies with different exposure cutpoints
T2 - A meta-analysis on body mass index and diabetes type 2
AU - Hartemink, Nienke
AU - Boshuizen, Hendriek C.
AU - Nagelkerke, Nico J.D.
AU - Jacobs, Monique A.M.
AU - Van Houwelingen, Hans C.
N1 - Funding Information:
This research was financed by the National Institute of Public Health and the Environment. The authors thank Dr. C. Baan and Dr. E. Feskens for their useful insights regarding the development of diabetes type 2 and the risk factors that may be involved. Conflict of interest: none declared.
PY - 2006/6
Y1 - 2006/6
N2 - Studies on a dose-response relation often report separate relative risks for several risk classes compared with a referent class. When performing a meta-analysis of such studies, one has to convert these relative risks into an overall relative risk for a continuous effect. Apart from taking the dependence between separate relative risks into account, this implies assigning an exposure level to each risk factor class and allowing for the nonlinearity of the dose-response relation. The authors describe a relatively simple method solving these problems. As an illustration, they applied this method in a meta-analysis of the association between body mass index and diabetes type 2, restricted to results of follow-up studies (n = 31). Results were compared with a more ad hoc method of assigning exposure levels and with a method in which the nonlinearity of the dose-response method was not taken into account. Differences with the ad hoc method were larger in studies with fewer categories. Not incorporating the nonlinearity of the dose response leads to an overestimation of the pooled relative risk, but this bias is relatively small.
AB - Studies on a dose-response relation often report separate relative risks for several risk classes compared with a referent class. When performing a meta-analysis of such studies, one has to convert these relative risks into an overall relative risk for a continuous effect. Apart from taking the dependence between separate relative risks into account, this implies assigning an exposure level to each risk factor class and allowing for the nonlinearity of the dose-response relation. The authors describe a relatively simple method solving these problems. As an illustration, they applied this method in a meta-analysis of the association between body mass index and diabetes type 2, restricted to results of follow-up studies (n = 31). Results were compared with a more ad hoc method of assigning exposure levels and with a method in which the nonlinearity of the dose-response method was not taken into account. Differences with the ad hoc method were larger in studies with fewer categories. Not incorporating the nonlinearity of the dose response leads to an overestimation of the pooled relative risk, but this bias is relatively small.
KW - Body mass index
KW - Diabetes mellitus
KW - Meta-analysis
KW - Obesity
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U2 - 10.1093/aje/kwj141
DO - 10.1093/aje/kwj141
M3 - Article
C2 - 16611666
AN - SCOPUS:33745620746
SN - 0002-9262
VL - 163
SP - 1042
EP - 1052
JO - American Journal of Epidemiology
JF - American Journal of Epidemiology
IS - 11
ER -