Biomedical subjects

J L Krull

Publications and source records attributed to J L Krull.

8 recordsLinked to original sources

PubMed2001

Mediating mechanisms in a program to reduce intentions to use anabolic steroids and improve exercise self-efficacy and dietary behavior.

This study investigated the mediating mechanisms responsible for the effects of a program designed to reduce intentions to use anabolic steroids, improve nutrition, and increase strength training self-efficacy. Fifteen of 31 high school football teams (N = 1,506 players at baseline) in Oregon and Washington were assigned to receive the intervention. The multicomponent program addressed the social influences promoting ergogenic drug use and engaging students in healthy nutrition and strength training alternative behaviors. Although the results differed across the three dependent variables, the program appeared to work by changing team norms. Unlike prevention of other drugs, changes in knowledge and perceived severity were mediators of program effects in this study.

Adolescent↗

PubMed2001

Acculturation and family functioning are related to health risks among pregnant Mexican American women.

The authors examined the independent and interactive effects of acculturation status and family cohesiveness on a series of psychosocial and medical risk factors of pregnancy among 500 women of Mexican origin. In general, both higher and lower levels of acculturation produced positive or negative psychosocial and healthcare consequences, and the operative relationships depended heavily on the particular outcome chosen. Higher levels of family cohesiveness tended to foster the most constructive health and psychosocial outcomes. However, in some circumstances higher levels of family cohesiveness resulted in less coping and a lower quality of prenatal care for less acculturated women. An important implication of this study is that psychosocial and health information can be obtained through assessments that identify different subgroups of Mexican American women and depend on women's level of acculturation and family cohesiveness. Culturally competent health practitioners or clinicians can conduct these assessments in a prenatal healthcare setting.

Acculturation↗

PubMed2000

Equivalence of the mediation, confounding and suppression effect.

This paper describes the statistical similarities among mediation, confounding, and suppression. Each is quantified by measuring the change in the relationship between an independent and a dependent variable after adding a third variable to the analysis. Mediation and confounding are identical statistically and can be distinguished only on conceptual grounds. Methods to determine the confidence intervals for confounding and suppression effects are proposed based on methods developed for mediated effects. Although the statistical estimation of effects and standard errors is the same, there are important conceptual differences among the three types of effects.

Bias↗

PubMed2000

The relation of personality to alcohol abuse/dependence in a high-risk sample.

The current study had two goals. The first goal was to test the mediational role of young adult personality in the relation between parental alcoholism and young adult alcoholism. The second was to examine the associations between personality and alcohol use motives and reasons to limit drinking in order to explore possible mechanisms by which personality may influence alcohol abuse/dependence. Multilevel modeling techniques were used to analyze data obtained from a community sample of young adult children of alcoholics and demographically matched controls. Results revealed that young adult neuroticism and agreeableness each, in part, mediated the effect of parental alcoholism on young adult alcoholism. Moreover, individuals high in neuloticism reported stronger coping motives to use alcohol, individuals low in agreeableness reported stronger coping motives and weaker upbringing reasons to limit drinking, and individuals low in conscientiousness reported stronger coping and enhancement motives to use alcohol, and weaker performance reasons to limit drinking.

Adolescent↗

PubMed1999

Multilevel mediation modeling in group-based intervention studies.

This article proposes and evaluates a method to test for mediation in multilevel data sets formed when an intervention administered to intact groups is designed to produce change in individual mediator and outcome variables. Simulated data of this form were used to compare ordinary least squares (OLS) and two multilevel estimators of the mediated effect. OLS and multilevel standard error approximations were also evaluated and recommendations given for optimal estimator choice. These methods were applied to data from an existing substance use intervention to show the impact multilevel mediation modeling can have on the conclusions drawn from real-world evaluation studies.

Analysis of Variance↗

PubMed1999

Determinants of birth-weight outcomes among Mexican-American women: examining conflicting results about acculturation.

In this article, we describe a comprehensive model for exploring the determinants of birth-weight outcomes among Mexican-American women from the Arizona Perinatal Acculturation Project. Data for this article came from a longitudinal study consisting of two phases. In phase one, a detailed prenatal survey was administered to 500 pregnant women. Phase two consisted of a postnatal survey administered to the women at least three months after they delivered (N = 269). Subjects who provided data were recruited from two health care agencies. Separate model building processes were conducted for a continuous measure of birth weight, and a dichotomous indicator of low-moderate birth weight (<2900 grams) using multiple linear and logistic regression analyses, respectively. The potential predictor variables for the models were divided into twelve predictor sets. The results showed that both final models included a combination of biological/behavioral factors, as well as protective sociocultural factor indicators. Acculturation status, one of the primary variables of interest in the study was found to be important for predicting birth weight and low-moderate birth weight. This result did not change when low birth weight (<2500 grams) infants were removed from the analyses. Low acculturation status was found to be associated with better birth-weight outcomes than high acculturation status. Surprisingly, length of US residence had an opposite effect in predicting both birth-weight indicators when compared to acculturation status. These results suggest that the relationships between acculturation and birth outcomes should be redefined to take into account the complexity of the phenomenon of acculturation in addition to the measurement of an array of family and sociocultural factors.

Acculturation↗

PubMed1996

Experimental personality designs: analyzing categorical by continuous variable interactions.

Theories hypothesizing interactions between a categorical and one or more continuous variables are common in personality research. Traditionally, such hypotheses have been tested using nonoptimal adaptations of analysis of variance (ANOVA). This article describes an alternative multiple regression-based approach that has greater power and protects against spurious conclusions concerning the impact of individual predictors on the outcome in the presence of interactions. We discuss the structuring of the regression equation, the selection of a coding system for the categorical variable, and the importance of centering the continuous variable. We present in detail the interpretation of the effects of both individual predictors and their interactions as a function of the coding system selected for the categorical variable. We illustrate two- and three-dimensional graphical displays of the results and present methods for conducting post hoc tests following a significant interaction. The application of multiple regression techniques is illustrated through the analysis of two data sets. We show how multiple regression can produce all of the information provided by traditional but less optimal ANOVA procedures.

Adaptation, Psychological↗

PubMed1995

Cancer risk reduction in Mexican American women: the role of acculturation, education, and health risk factors.

This article describes a two-factor schema for the development of culturally appropriate cancer risk reduction interventions for Mexican American women. Regarding this approach, risk factors for two major cancer areas are reviewed: cigarette smoking and obesity/diet. We first describe a schema that facilitates the planning of strategies associated with preferred health interventions and preventive approaches for cancer risk reduction with Mexican American and other Latino/Hispanic persons. This schema examines Acculturation and Education as key factors that should be considered in developing health education messages and interventions that are culturally and educationally appropriate to the identified subpopulations of Hispanics in terms of language and informational content of the message and in terms of psychological factors related to health behavior change. Empirical data from a community sample is presented for the purpose of illustrating the validity of this schema. Then we review studies that examine the effect of acculturation on the distribution of the risk factors, based on studies in the current literature. Here we note the target group of women with the highest risk, based on the available information on Acculturation and other sociodemographic factors. Additionally, an illustration is presented where information and the concepts offered by the two-factor schema facilitate the analysis of (a) health education message needs and (b) needed behavior change, thus pointing to (c) more appropriate health promotion strategies for targeted Hispanic/Latino individuals or groups. The information described in this article aims to help program planners, researchers, and health educators in the design of more effective programs of health intervention for Mexican American and other Hispanic/Latino women.

Acculturation↗