John A. Martin

Sexual Maturation, Social Class, and the Desire to Be Thin Among Adolescent Females

Veblens 1899 hypothesis that associated a female desire for thinness with the higher social classes was tested with data from a representative national sample of adolescents, 12 to 17 years of age, in the National Health Examination Survey. Controlling for the actual level of fatness, adolescent females in higher social classes wanted to be thinner more often than those in lower classes. The greater female desire for thinness was not the product of health information nor of sex differences in the level of fatness. The thinner the female, the greater the impact of social class on the desire for thinness. During puberty, adolescent females negatively evaluated the body fat associated with normal sexual development.

Sexual development age and dating: a comparison of biological and social influences upon one set of behaviors.

Data from the U.S. National Health Examination Survey of 12-17-year-old youths were used to determine whether the development of the social behavior of dating is more closely linked to the level of sexual maturation or to the progression through age grades without reference to sexual maturation. Regression analyses and partial correlations show that individuals levels of sexual maturation add very little to the explained variance in dating after age had been taken into account. It appears that social pressures, based on behavior considered typical and appropriate at various ages, determines the onset of dating in adolescents. Individual rates of sexual maturation that deviate from the norm for that age have little impact on dating. These findings show how social standards can reduce dramatically the impact of individual biological processes on institutionalized forms of behavior.

Educational correlates of early and late sexual maturation in adolescence

From the National Health Examination Survey data, 4,735 Caucasian males and females, 12 to 17 years, were classified by age and stage of sexual maturation (Tanner). Early and late maturers were each compared to all other youth of comparable age and sex, in eight education-related categories: youth and parental aspirations and expectations concerning the level of education which would be achieved by the student, teacher reports of intellectual ability and academic achievement, and test scores (WISC and WRAT). Except at age 12, late maturing boys received significantly lower ratings than mid maturers in all these areas, and early maturing males received higher ratings. For females, no differences persisted across age groups. In advising male adolescents, physicians should be alert to the possibility that school functioning may be linked to maturational processes.

Structural Equation Modeling: A Guide for the Perplexed.

MARTIN, JOHN A. Structural Equation Modeling: A Guide for the Perplexed. CHILD DEVELOPMENT, 1987, 58, 33-37. Despite seemingly incomprehensible notation and statistical complexity, the basic logic behind latent-variable structural equation modeling is quite simple. These methods are essentially an extension of familiar techniques such as multiple regression and factor analysis. In this light, readers are provided with a set of 5 statements and questions to guide them in their attempts to decipher reports of research employing structural modeling methods.

HEART RATE, TcP02 AND TACTILE STIMULI PRECEDING BRADY CARDIA IN PRETERM INFANTS

Attempting to identify predictive antecedents to bradycardia in preterm infants, we analyzed 6500 minutes of heart rate and transcutaneous oxygen patterns of 9 infants who had bradycardic episodes during continuous computerized observations. Sixteen measures of heart rate and TcPO2 recorded 5 minutes before a bradycardic episode were compared with baseline values of these variables for the day when each bradycardia occurred. There were 50 episodes of bradycardia isolated by more than 5 minutes from any prior episode. Infants were handled 5 minutes before bradycardia in 29 of the 50 instances. Over the 5 minutes before bradycardia, the mean of the minimum TcPO2s, the absolute minimum TcPO2 and the mean of the TcPO2s were all lower than baseline 24 of 29 times when touch preceded bradycardia (p <.01). However, when no caregiver touch occurred prior to bradycardia, these same 3 TcPO2 variables were recorded higher than baseline for the 5-minute pre-bradycardic period. In the absence of touch, the mean heart rate as well as the maximum variability in high - low heart rates were lower than baseline 14 of 21 times during the pre-bradycardic period. These results generate the hypothesis that preterm infants who are handled when TcPO2 is low are very prone to subsequent bradycardia. Bradycardia following handling appears to have a different and potentially more preventable causative mechanism from spontaneously occurring episodes.

78 SOCIAL SUPPORT AND STRESS IN MOTHERS OF ASTHMATIC CHILDREN: RELATIONSHIP TO MORBIDITY

Social support and stress have been shown to modify the course of chronic illness in adults. This has not been examined in the pediatric population although clinical observations suggest that maternal social support and stress may affect the outcome of a childs chronic illness. This study examines the relationship between these maternal factors and the asthmatic childs morbidity.A group of 35 mothers of asthmatic children seen at Childrens Hospital at Stanford completed a questionnaire assessing their social support, stress and compliance with medical care. Baseline morbidity data were collected by maternal recall of emergency room visits (ER) and hospitalizations for the childs asthma over the past year, type of medication used and the mothers perception of the severity of the asthma.Chi-square analysis of the data showed: 1) mothers with low social support perceived increased severity of their childrens asthma, 2) children of mothers with small social networks had more ER visits per year and 3) while maternal stress alone was unrelated to morbidity, mothers who had both high stress and small social networks had children with more ER visits per year than other groups. Neither social support nor stress were related to the degree of asthma, seasonality or type of medication used.These data suggest that measures of maternal social support and stress can delineate a subgroup of mothers whose children have higher morbidity and who may derive maximum benefit from supportive care by health professionals.

9 LINEAR GROWTH DURING PUBERTY: IMPACT OF PUBERTAL DEVELOPMENT

Short stature is a frequent complaint of adolescent males. The pediatricians ability to interpret this concern is largely dependent upon use of standard growth curves. These curves are based only on chronological age and do not reflect the impact of sexual maturation on height. Accordingly, we undertook to revise these curves to enhance their usefulness.Using National Health Examination Survey data from 3,000 male adolescents, ages 12 to 17, we constructed height curves for each stage of sexual maturation and age. The resulting graphs depict estimated percentiles for height at each stage of sexual maturation from ages 12 to 17.Applications: a 145 cm 13 year old boy with a Sex Maturity Rating (S.M.R.) of 1, is later in sexual maturation and shorter than his age mates with his height measuring below the 10th percentile on standard height charts. When compared with other S.M. R. 1, 13 year old males, his height is at almost the 25th percentile. For the 150 cm 14 year old boy with a S.M.R. of 2, his percentile moves from 5th-10th percentile on the standard growth curve to approximately the 20th percentile on the curves adjusted for stage of sexual maturation.Our data provide pediatricians with a more precise way of evaluating adolescent male height and may offer information potentially reassuring to the short, late-maturing adolescent male and his parents.