Biomedical subjects

Laurie DeChello

Publications and source records attributed to Laurie DeChello.

3 recordsLinked to original sources

PubMed2006

Effects of study area size on geographic characterizations of health events: prostate cancer incidence in Southern New England, USA, 1994-1998.

BACKGROUND: We consider how representations of geographic variation in prostate cancer incidence across Southern New England, USA may be affected by selection of study area and/or properties of the statistical analysis. METHOD: A spatial scan statistic was used to monitor geographic variation among 35,167 incident prostate cancer cases diagnosed in Massachusetts, Connecticut and Rhode Island from 1994 to 1998, in relation to the 1990 populations of men 20+ years of age living in that region. Results from the combined-states analysis were compared to those from single-states. Impact of scanning procedures set to examine up to 50% or no more than 10% of at-risk populations also was evaluated. RESULTS: With scanning set to 50%, 5 locations in the combined-states analysis were identified with markedly distinct incidence rates. Fewer than expected cases were estimated for nearly all Connecticut, Rhode Island and West Central Massachusetts, whereas census tracts on and around Cape Cod, and areas of Southwestern Connecticut and adjacent to greater Boston were estimated to have yielded more than expected incidence. Results of single-state analyses exhibited several discrepancies from the combined-states analysis. More conservative scanning found many more locations with varying incidence, but discrepancies between the combined- and single-state analysis were fewer. CONCLUSION: It is important to acknowledge the conditional nature of spatial analyses and carefully consider whether a true cluster of events is identified or artifact stemming from selection of study area size and/or scanning properties.

Adult↗

PubMed2006

Cancer map patterns: are they random or not?

BACKGROUND: Maps depicting the geographic variation in cancer incidence, mortality or treatment can be useful tools for developing cancer control and prevention programs, as well as for generating etiologic hypotheses. An important question with every cancer map is whether the geographic pattern seen is due to random fluctuations, as by pure chance there are always some areas with more cases than expected, or whether the map reflects true underlying geographic variation in screening, treatment practices, or etiologic risk factors. METHODS: Nine different tests for spatial randomness are evaluated in very practical settings by applying them to cancer maps for different types of data at different scales of spatial resolution: breast, prostate, and thyroid cancer incidence; breast cancer treatment and prostate cancer stage in Connecticut; and nasopharynx and prostate cancer mortality in the U.S. RESULTS: Tango's MEET, Oden's Ipop, and the spatial scan statistic performed well across all the data sets. Besag-Newell's R, Cuzick-Edwards k-NN, and Turnbull's CEPP often perform well, but the results are highly dependent on the parameter chosen. Moran's I performs poorly for most data sets, whereas Swartz Entropy Test and Whittemore's Test perform well for some data sets but not for other. CONCLUSIONS: When publishing cancer maps we recommend evaluating the spatial patterns observed using Tango's MEET, a global clustering test, and the spatial scan statistic, a cluster detection test.

Adolescent↗

PubMed2004

Rate of change in functional limitations for patients with rheumatoid arthritis: effects of sex, age, and duration of illness.

OBJECTIVE: To estimate the rate of change in functional limitations for patients with rheumatoid arthritis (RA) as a function of age, duration of illness, and sex. METHODS: Patients with RA (n = 700) aged 21-65 years in 1988 were interviewed yearly for 6 years in The National Rheumatoid Arthritis Study. Functional limitations scores based on a Rasch measurement model of 20 Health Assessment Questionnaire items were analyzed in mixed-effects models to estimate the rate of change in functional ability as a function of age, duration of illness, sex, and interactions. RESULTS: Models for both patient age and duration of illness significantly predicted limitations in functional ability for men and women. The model for age included a significant cubic effect; the model for duration of illness included a significant linear effect only. Sex was significant in both models and no interactions were significant in either model. The AIC index of fit, an indicator of the information value of the model, favored the model for duration of illness over the model for age. While both models showed higher levels of functional limitations in women than men, the rate of change for women was similar to men. CONCLUSION: Limitation in functional ability in RA progressed in a linear manner with duration of illness and progressed at the same rate for both men and women, but functional limitations were greater for women.

Activities of Daily Living↗