In the past year, my research on this project was concentrated in three areas: (1) incidence and mortality analyses of cancer unrelated to smoking or screening, (2) comparisons of statewide and national data on the incidence of non-Hodgkin's lymphoma (NHL), and (3) ecologic assessment of the effect of arsenic in ground water on cancer incidence. Research in these areas involved APC analyses, joinpoint analyses, and spatial analyses. This work is collaborative with researchers at the University of Pittsburgh. The three areas of research are described in more detail below.? ? Area 1:? ? We studied temporal patterns of cancer incidence and mortality rates in the United States based on data from the SEER program. The incidence data were from 1975-2004 and the mortality data were from 1970-2004. We used APC models to investigate the effects of age group, time period, and birth cohort on the rates of cancer in three categories: cancers related to tobacco smoking, cancers detectable by screening, and all other cancers. Our primary focus was on the last category, which corresponds to cancers whose temporal patterns should not be easily explained by changes related to tobacco smoking or screening techniques. Within this last category, we paid particular attention to NHL.? ? Our APC model was parameterized in terms of long-range trends and deviations from those trend lines. The deviations from linearity can be uniquely attributed to age, period, or cohort effects, but the slopes of the trend lines cannot. The long-range trends were summarized in terms of combined period and cohort effects, for which the corresponding slope can be uniquely estimated. Overall, for cancer unrelated to smoking or screening, incidence rates increased and mortality rates decreased among black and white men and women. In fact, long-range trends in NHL were positive for both incidence and mortality rates. Deviations from linearity were significant, however, for cancers unrelated to smoking or screening in general and for NHL in particular. Thus, the long-range trends do not tell the whole story with respect to the temporal effects on these cancer patterns.? ? A manuscript is in preparation and should be ready to submit to a scientific journal in the next month or two.? ? Area 2:? ? We investigated the incidence of NHL in greater detail. Specifically, we studied the effects of both temporal and demographic factors on NHL incidence rates. Also, we used data from both the SEER registry and the Pennsylvania Cancer Registry (PCR), which is not part of the SEER program. We employed APC and joinpoint models to analyze the data. Relative to the APC analysis, the joinpoint analysis averages over age groups and does not account for cohort effects, but it can accommodate multiple trend lines that are joined at arbitrary points along the calendar year (period) scale. The results from the national and statewide registries, as well as from the APC and joinpoint analyses, were compared and contrasted.? ? Based on data from 1985 to 2004, the SEER and PCR results were fairly similar with respect to temporal patterns of NHL incidence. According to both the APC and joinpoint analyses, the incidence of NHL increased between 1985 and 2004 among black and white men and women, both nationally and in Pennsylvania. Diffuse lymphoma appeared to be the most important component of this increase. In Pennsylvania, NHL incidence was higher in counties with a greater percentage of urban residents.? ? A manuscript is in preparation and should be ready to submit to a scientific journal in a few months.? ? Area 3:? ? We also performed an ecologic study of the relationship between arsenic levels in ground water and cancer incidence in Idaho. Using 1990-2005 data from the Cancer Registry of Idaho and the Idaho Department of Environmental Quality, we used spatial autocorrelation analysis to identify geographic patterns of incidence rates for NHL, bladder cancer, kidney cancer, liver cancer, lung cancer, and all cancers combined. We employed spatial regression analysis to evaluate the relationship between ground water arsenic levels and cancer incidence rates.? ? We identified various geographic clusters of certain cancers, some of which were gender-specific. Cancer incidence was correlated with several explanatory factors, such as gender, race, smoking history, and body mass index, but we found no evidence that exposure to arsenic in ground water was associated with cancer incidence rates.? ? A manuscript is in preparation and should be ready to submit to a scientific journal in a few months.
