Biomedical subjects

F B Hu

Publications and source records attributed to F B Hu.

79 records · Page 5Linked to original sources

PubMed1996

Intraclass correlation estimates in a school-based smoking prevention study. Outcome and mediating variables, by sex and ethnicity.

Most school-based smoking prevention studies employ designs in which schools or classrooms are assigned to different treatment conditions while observations are made on individual students. This design requires that the treatment effect be assessed against the between-school variance. However, the between-school variance is usually larger than the variance that would be obtained if students were individually randomized to different conditions. Consequently, the power of the test for a treatment effect is reduced, and it becomes difficult to detect important treatment effects. To assess the potential loss of power or to calculate appropriate sample sizes, investigators need good estimates of the intraclass correlations for the variables of interest. The authors calculated intraclass correlations for some common outcome variables in a school-based smoking prevention study, using a three-level model-i.e., students nested within classrooms and classrooms nested within schools. The authors present the intraclass correlation estimates for the entire data set, as well as separately by sex and ethnicity. They also illustrate the use of these estimates in the planning of future studies.

Adolescent↗

PubMed1994

Differential influence of parental smoking and friends' smoking on adolescent initiation and escalation of smoking.

Smoking-related behaviors and attitudes of significant others (especially friends and parents) are among the most consistent predictors of adolescent smoking. However, theorists remain divided on whether the behaviors of significant others influence adolescent smoking directly or indirectly, and the relative influence of parental and peer smoking on adolescents' own smoking is still a matter of debate. In addition, little research has examined the role of significant others' behavior on different stages of smoking onset. In particular, not much information is available regarding gender and ethnic differences in social influences on smoking behavior. We use structural equation modeling to address these issues. Different theoretical perspectives from cognitive-affective theories (Ajzen 1985; Ajzen and Fishbein 1980) and social learning theories (Akers et al. 1979; Bandura 1969, 1982, 1986) have been integrated into a structural model of smoking influence. The results show that friends' smoking affects adolescent initiation into smoking both directly and indirectly, whereas parental smoking influences smoking initiation only indirectly. The data also show that friends' and parents' smoking affect smoking escalation only indirectly. In general, friends' smoking has a stronger effect on adolescents' smoking behavior, particularly on initiation. Multiple group comparisons of the structural models predicting smoking initiation among males and females reveal that parental approval of smoking plays a significant mediating role for females, but not for males. Comparisons of Whites, Blacks, Hispanics, and other ethnic groups reveal that there are some significant differences in the pathways of friends' influences among the four groups.

Adolescent↗

PubMedDate not supplied

Dietary patterns and the risk of coronary heart disease in women.

BACKGROUND: Although substantial information on individual nutrients or foods and risk of coronary heart disease (CHD) is available, little is known about the role of overall eating pattern. METHODS: Using dietary information from a food frequency questionnaire in 1984 from the Nurses' Health Study, we conducted factor analysis and identified 2 major dietary patterns-"prudent" and "Western"-and calculated factor scores of each pattern for individuals in the cohort. We used logistic regression to examine prospectively the associations between dietary patterns and CHD risk among 69 017 women aged 38 to 63 years in 1984 without history of major chronic diseases. RESULTS: The prudent pattern was characterized by higher intakes of fruits, vegetables, legumes, fish, poultry, and whole grains, while the Western pattern was characterized by higher intakes of red and processed meats, sweets and desserts, french fries, and refined grains. Between 1984 and 1996, we documented 821 CHD cases. After adjusting for coronary risk factors, the prudent diet score was associated with a relative risk (RR) of 0.76 (95% confidence interval (CI), 0.60-0.98; P for trend test,.03) comparing the highest with lowest quintile. Extreme quintile comparison yielded an RR of 1.46 (95% CI, 1.07-1.99; P for trend test,.02) for the Western pattern. Those who were jointly in the highest prudent diet quintile and lowest Western diet quintile had an RR of 0.64 (95% CI, 0.44-0.92) compared with those with the opposite pattern profile. CONCLUSION: A diet high in fruits, vegetables, whole grains, legumes, poultry, and fish and low in refined grains, potatoes, and red and processed meats may lower risk of CHD.

Adult↗

PubMedDate not supplied

Factors affecting attrition in a longitudinal smoking prevention study.

BACKGROUND: In longitudinal smoking prevention studies, a difficulty in evaluating treatment effects is understanding whether bias is associated with those who do not complete the study. This study presents the significant predictors of attrition and suggests how to reduce attrition bias in evaluating program effects. METHODS: Survival analysis methods were used to assess factors associated with attrition at different time points of the study. RESULTS: Results of the analysis indicate that those who drop out tend to be of lower academic achievement, have lower tobacco and health knowledge, and have lower social influence/resistance skills knowledge, and are more likely to be smokers and to be marijuana users. Blacks are more likely to drop out than the other ethnic groups. Gender is not a significant predictor for dropout. The dropout rates among the treatment conditions are significantly different. CONCLUSIONS: The findings of this study demonstrate that attritions in longitudinal smoking prevention studies are not at random. By considering the characteristics of dropouts, one can reduce attrition bias using available procedures and can take appropriate strategies for reducing dropout rates in future smoking prevention studies.

Adolescent↗

PubMedDate not supplied

Psychosocial predictors of different stages of cigarette smoking among high school students.

BACKGROUND: Current research on the etiology of cigarette smoking has largely focused on the identification of psychosocial predictors of tobacco onset. Few data are available on the predictors of different stages of smoking among adolescents. The present study examines the psychosocial predictors of different stages of smoking, including trial, experimental, and regular use, among high school students. METHOD: The predictor variables were measured when the students were in the 7th grade. Logistic regression was used to predict different smoking stages at grade 12. RESULTS: The results show that four domains of psychosocial variables, including social and interpersonal factors, attitudinal and belief factors, intrapersonal factors, and use of other substances, predicted one or more stages of smoking. The important correlates of transition from trial to experimental use (all P value <0.001) included friends' smoking and approval, cigarette offers by friends, smoking intentions, school grade, and alcohol and marijuana use. The significant predictors of the transition from experimental to regular use included only parental smoking (P < 0.01) and family conflicts (P < 0.05). We found some gender differences in these predictors. CONCLUSIONS: Psychosocial predictors may differ by different stages of smoking.

Adolescent↗

PubMedDate not supplied

Patterns of use of smokeless tobacco and the unidimensional model of drug involvement.

The present study tested whether smokeless tobacco (ST) fits a unidimensional model of drug involvement and tried to locate ST along the dimension that underlies drug use. The latent trait analysis was employed to quantify drug involvement in a sample of high school students. Analyses showed that although ST use fits the unidimensional model of drug involvement, the place of ST use along the continuum of drug involvement is not stable and differs by gender and ethnicity. Particularly for males, ST use is likely to be preceded by soft drug use and followed by hard drug use; for females, however, ST use is closely associated with hard drug use. The analyses also revealed that the fit of the unidimensional model and the location of ST use along the dimension vary with different ethnic groups.

Adolescent↗

PubMedDate not supplied

The patterns and predictors of smokeless tobacco onset among urban public school teenagers.

This study describes the patterns and predictors of smokeless tobacco (ST) use in a large sample of urban public school students in Los Angeles and San Diego. The use of ST is more common among men than women and among Caucasians than African Americans, Hispanics, and others. Approximately 20% of the male respondents and 5% of the female respondents reported use of ST at least once, and 10.1% of male students and 3.1% of female students who had never tried ST by seventh grade started to use it by eighth grade. Among Caucasians, about 30% of boys reported trying ST at least once and 13.7% of those who had never used ST by seventh grade initiated experimentation by eighth grade. These data are used to examine the family, peer, and intrapersonal predictors of ST onset. The family risk factors for ST onset include living with a single parent, parent-child conflicts, and parental alcohol use. The peer risk factors for ST use include peer drug use and activities with friends, such as parties and participation in sports. The intrapersonal risk factors include poor grades in school, risk taking, and stress. The study also shows that those who use cigarettes, alcohol, or marijuana are at higher risk of using ST and vice versa. This study supports a problem-prone behavior perspective of ST use and cigarette smoking. We suggest that both products be targeted because the same programs are likely to apply to both products to counteract problem-prone type variables. Medical Subject Headings (MeSH): tobacco, smokeless chewing tobacco, adolescent behavior.

Adolescent↗