Generalized Additive Models and Inflated Type I Error Rates of Smoother Significance Tests.

Generalized additive models (GAMs) have distinct advantages over generalized linear models as they allow investigators to make inferences about associations between outcomes and predictors without placing parametric restrictions on the associations. The variable of interest is often smoothed using a locally weighted regression (LOESS) and the optimal span (degree of smoothing) can be determined by minimizing the Akaike Information Criterion (AIC). A natural hypothesis when using GAMs is to test whether the smoothing term is necessary or if a simpler model would suffice.

A power comparison of generalized additive models and the spatial scan statistic in a case-control setting.

Background: A common, important problem in spatial epidemiology is measuring and identifying variation in disease risk across a study region. In application of statistical methods, the problem has two parts. First, spatial variation in risk must be detected across the study region and, second, areas of increased or decreased risk must be correctly identified.

A multilevel non-hierarchical study of birth weight and socioeconomic status.

Background: It is unclear whether the socioeconomic status (SES) of the community of residence has a substantial association with infant birth weight. We used multilevel models to examine associations of birth weight with family- and community-level SES in the Cape Cod Family Health Study. Data were collected retrospectively on births to women between 1969 and 1983 living on Cape Cod, Massachusetts.

Caregiver health literacy and adherence to a daily multi-vitamin with iron regimen in infants.

Objective: To determine whether or not limited caregiver health literacy is associated with adherence to a daily multi-vitamin with iron regimen in infants.

Methods: 110 caregiver/infant dyads were enrolled in a prospective study to assess the relationship between caregiver health literacy and adherence to a daily multi-vitamin with iron regimen for infants. Households were contacted biweekly over a 3-month period.

Implications of subdividing marital status: are unmarried mothers with partners different from unmarried mothers without partners? An exploratory analysis.

Objective: To determine the analytic advantages obtained from separating unmarried mothers with partners from unmarried mothers without partners when assessing risk of adverse birth outcomes.

Methods: Data were obtained from Listening to Mothers II, a national survey of women's childbearing experiences. Marital status was asked with three choices: married (71%), unmarried with partner (24%), and unmarried without partner (5%).

Food insecurity and compensatory feeding practices among urban black families.

Objective: In this we study explored the relationship between food insecurity and compensatory maternal feeding practices that may be perceived as buffers against periodic food shortages among urban black families.

Methods: We interviewed a convenience sample of black mothers of children aged 2 to 13 years. Food-security status (predictor) was determined at the household level.