Using splines to analyse latency in the Colorado Plateau uranium miners cohort.
BACKGROUND
Different approaches have been proposed to investigate latency in epidemiologic studies where detailed exposure histories are available.


METHODS
We demonstrate the application of a flexible, yet parsimonious, spline function model to investigate latency patterns for radon progeny exposure and lung cancer in the Colorado Plateau uranium miners cohort. The model extends a previously proposed bilinear model.


RESULTS
The excess relative risk (ERR) reached a maximum of 0.6 per 100 working level months, for exposures received 14 years previously. The ERR then declined, and was estimated to approach zero for exposures received 35 years and more in the past. The point-wise 95% confidence intervals supported ERRs > 0 for the period 9-32 years before the event. The estimated latency curve was homogeneous across categories of attained age, duration of exposure, rate of exposure, and smoking.


CONCLUSIONS
The proposed spline model is a flexible tool for latency analyses, and extends previously used methods.
Hauptmann
M
M
Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda MD 20892-7244, USA.
Berhane
K
K
Langholz
B
B
Lubin
J
J
D000328:Adult; D000368:Aged; D000396:Air Pollutants, Radioactive / Q000009:adverse effects*; D002274:Carcinogens, Environmental / Q000009:adverse effects*; D003120:Colorado / Q000453:epidemiology; D004781:Environmental Exposure / Q000009:adverse effects; D016021:Epidemiologic Studies; D006207:Half-Life; D006801:Humans; D008175:Lung Neoplasms / Q000453:epidemiology* / Q000209:etiology; D008875:Middle Aged; D008906:Mining / Q000706:statistics & numerical data*; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology* / Q000209:etiology; D009784:Occupational Diseases / Q000453:epidemiology* / Q000209:etiology; D011886:Radon / Q000009:adverse effects*; D018570:Risk Assessment; D013223:Statistics as Topic; D013997:Time Factors; D014501:Uranium / Q000009:adverse effects
D000396:Air Pollutants, Radioactive; D002274:Carcinogens, Environmental; D014501:Uranium; D011886:Radon