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Biomedical subjects

J R Udry

Publications and source records attributed to J R Udry.

85 records · Page 5Linked to original sources

Biosocial models of adolescent problem behaviors.

This paper develops a biosocial model of adolescent age-graded norm violations ("problem behaviors"), combining a traditional social control model with a biological model using steroid hormones. Subjects were 101 white boys drawn from the 8th-, 9th-, and 10th-grade rosters of selected public schools, and ranging in age from 13 to 16. Subjects completed self-administered questionnaires and provided blood samples which were assayed for the behaviorally relevant hormones. Boys' problem behavior shows strong hormone effects. Social and biological variables have both additive and indirect effects. Using a biosocial model leads to conclusions which are different from those which would have been drawn from the sociological model alone.

Adolescent↗

Biosocial models of adolescent problem behavior: extension to panel design.

We extended the biosocial model of problem behavior tested by Udry (1990) to a panel design, following a sample of over one hundred boys in adolescence for three years. We found the expected results for sociological variables, but weaker effects for testosterone than Udry found on cross-sectional data. Using panel models with lagged hormone effects, we identified relationships between Time-1 testosterone and problem behavior one year or more later. The relationship between testosterone and problem behavior was not present for subsequent measures of testosterone, either in cross-section or with time-lagged models. Therefore we cannot interpret the results as showing testosterone effects on problem behavior. Rather it appears that testosterone level in early adolescence is a marker for a more general growth trajectory of early development.

Adolescent↗

Relationships between aggression and pubertal increases in testosterone: a panel analysis of adolescent males.

Existing data linking testosterone (T) and aggression in human adult males are surprisingly tenuous. In one of the few studies based on adolescent males, Olweus et al. (1988) demonstrated strong relationships between concurrent measures of T and aggression. However, the conclusions that could be drawn regarding developmental change were limited. Using data from a three-year panel study of 100 adolescent males (ages 12 to 13 at study entry), we examined whether there are significant relationships between concurrently collected measures of T and self-ratings of aggression, and whether the dramatic pubertal rise in T predicts subsequent change in aggression ratings. Panel analyses incorporating concurrent, lagged, and change measures found few significant relationships between aggression and T or pubertal development. The general absence of T/aggression relationships is discussed in the context of other empirical findings, the aggression measures used, and prepubertal differentiation on aggression.

Adolescent↗

Testosterone and pubertal development as predictors of sexual activity: a panel analysis of adolescent males.

Strong cross-sectional relationships between testosterone (T) and sexual activity have been found for human adolescent males, even when level of pubertal development is controlled; however, it has not been demonstrated that sexual behavior increases over time as a consequence of hormonal changes. The purpose of this paper was to extend previous cross-sectional findings by demonstrating that sexual behavior is initiated and increases within individuals over time as a direct function of changes in T levels, rather than indirectly through pubertal development. Analyses are based on a 3-year panel study of about 100 7th- and 8th-grade adolescent boys. Pubertal development and changes in pubertal development were significantly and positively related to changes in sexual ideation, noncoital behavior, and to the transition to sexual intercourse. Testosterone levels at study entry were significantly related to coital status at Time 1 and also predicted the transition to nonvirgin status. However, changes in hormone levels during the 3 years of study participation did not predict changes in ideation or noncoital sexual activity, regardless of the period of change or the lag time to effects. The panel data suggest, in contrast to earlier cross-sectional results, that change in pubertal development is related to the initiation of sexual activity because of its social stimulus value, and not solely because it is determined by, or is a proxy for, changing hormone levels. Possible causes of the different findings in the cross-sectional and panel data are examined, and the implications and meaning of hormone/behavior relationships based on single measures are discussed.

Adolescent↗

Testosterone predicts initiation of coitus in adolescent females.

OBJECTIVE: The purposes of this study were to demonstrate, using longitudinal data, that the pubertal rise in testosterone (T) is associated with subsequent increases in female sexual interest and activity, and to examine these relationships within the context of a social control variable. METHODS: Using data from a 2-year panel study of approximately 200 black and white postmenarcheal adolescent females, the relationships among semiannual measures of T, sex hormone binding globulin (SHBG), pubertal development, and self-reports of coital and noncoital sexual activity were assessed. RESULTS: Testosterone and changes in T were significantly related to the timing of subsequent transition to first coitus for blacks and whites. Frequency of attendance at religious services operated as a social control variable among white females, and was found to moderate T effects on sexual transition for this group. CONCLUSIONS: These results are consistent with a biosocial model proposing T as a causal factor in female sexual activity, and suggest that biological effects are moderated by relevant social variables.

Adolescent↗

Parent-child communication and adolescent sexual behavior.

Data collected over a two-year period from more than 500 teenagers and their mothers indicate that neither parental attitudes toward premarital sex nor parent-child communication about sex and contraception appear to affect teenagers' subsequent sexual and contraceptive behavior. Teenagers are often ignorant of their parents' attitudes toward sex-related issues, and they and their parents often contradict one another in describing the kinds of sex-related conversations they have had. In only two cases was a significant relationship found between communication and adolescent behavior: Girls whose mothers reported that they had discussed sex with their daughters were less likely to subsequently initiate coitus; and girls who reported that their mothers had discussed birth control with them were more likely to use effective contraceptives. However, the former association disappeared when it was the daughters who reported the communication, and the latter disappeared when it was the mothers who reported it.

Adolescent↗

Early predictors of nonmarital first pregnancy and abortion.

Most research on abortion has focused on women's characteristics at the time of the procedure, but individuals' behavior may also be shaped by their experiences from younger ages. This study uses longitudinal data on 351 California white women aged 27-30 in 1990-1991 to identify characteristics in childhood and adolescence that predict who will have a nonmarital first pregnancy and, of those who do, which women will seek an abortion. Bivariate analyses reveal that psychosocial characteristics indicating a strong sense of autonomy, such as feeling it is important not to be tied down and engaging in socially undesirable behavior, are significantly associated with the likelihood of having a nonmarital first pregnancy (odds ratios of 1.7 and 1.5, respectively), but family characteristics are not. However, among women who have a first pregnancy out of wedlock, the odds of having an abortion are mostly influenced by family rather than psychological characteristics, particularly having been a good student and having a well-educated mother (2.0 and 1.7).

Abortion, Induced↗

A medical record linkage analysis of abortion underreporting.

Inaccuracy in women's reports of their abortion histories affects many areas of interest to reproductive health professionals and researchers. The identification of characteristics that affect the accuracy of reporting is essential for the improvement of data collection methods. A comparison of the medical records of 104 American women aged 27-30 in 1990-1991 with their self-reported abortion histories revealed that 19% of these women failed to report one or more abortions. Results of logistic regression analysis indicate that nonwhite women were 3.3 times as likely as whites to underreport. With each additional year that had elapsed since the first recorded abortion, women became somewhat more likely to underreport (odds ratio of 1.3), while each additional year of a woman's education slightly decreased the likelihood of underreporting (odds ratio of 0.7).

Abortion, Induced↗