Sylvia Tan

Heritability of Subclinical Atherosclerosis in Latino Families Ascertained Through a Hypertensive Parent

Although clinical coronary heart disease and many cardiovascular risk factors are well known to aggregate within families, the heritability of carotid artery intima-media thickness (IMT) is less well documented. We report IMT heritability estimates in Mexican American, Salvadoran American, or Guatemalan American (all referred to as Latino) families ascertained through a hypertensive proband. IMT and cardiovascular risk factors (age, sex, blood pressure, body mass index, lipids, fasting glucose, and insulin sensitivity) were measured in 204 adult offspring of 69 hypertensive probands, along with 82 parents (54 probands and 28 spouses). In the offspring, variance component analysis revealed a heritability for IMT of 64% (P < 0.0001) after adjustment for significant cardiovascular risk factors. Genetic factors accounted for 50% of the total variation in IMT, whereas significant cardiovascular risk factors explained 22% (14% were due to age). For offspring and parents combined, adjusted IMT heritability was less, 34% (P =0.0005), with genetic factors accounting for 18% of the total IMT variation, whereas significant cardiovascular risk factors explained 46% (38% were due to age). We conclude that variation in c ommon carotid artery IMT is heritable in Latino families with a hypertensive proband. Heritability is particularly evident in younger family members, suggesting that acquired factors contribute progressively to IMT variability with aging.

The September 11th 2001 Terrorist Attacks and Reports of Posttraumatic Growth among a Multi-Ethnic Sample of Adolescents

Correlates of posttraumatic growth (PTG), the construing of benefits from a traumatic event, attributed to the September 11th terrorist attacks were examined among 513 middle school adolescents (mean age=13.5 years; 63% female; 44% Hispanic/Latino, 25% Asian, 16% White, 10% multiethnic/other, and 4% Persian; all residing in California). One-third of the participants, on average, reported experiencing positive changes post- 9/11 in the following areas: appreciation of life, life priorities, spirituality, relationships, and self-reliance. Hispanic and White, compared to Persian (largely Iranian), participants had significantly higher PTG scores. Discussion of the terrorist attacks, identification with a religion, and optimism were positively associated with PTG, while alcohol use, depressive symptoms, and anxiety were inversely associated with PTG. Ethnicity, discussion of the terrorist attacks, identification with a religion, optimism, anxiety, and alcohol use remained associated with PTG after adjusting f...

Adolescent smoking in Wuhan, China: baseline data from the Wuhan Smoking Prevention Trial.

BACKGROUND This study reports the prevalence of adolescent smoking in the urban and rural areas of Wuhan, China, the capital of Hubei Province, on the Yangtze River in central China. METHODS Smoking behavior was examined by age, gender, and urbanicity as part of the Wuhan Smoking Prevention Trial. Subjects included 6994 seventh- to ninth-grade students attending 22 randomly selected schools in urban and rural districts. Outcome measures included lifetime smoking, past-30-day smoking, established smoking (>100 cigarettes in lifetime), and susceptibility to smoking (absence of a firm commitment not to smoke). RESULTS Lifetime smoking prevalence was 47% among boys and 18% among girls. Past-30-day smoking prevalence was 16% among boys and 4% among girls. Established smoking prevalence was 2% among boys and 0% among girls. The prevalence of susceptibility to smoking was 31% among boys and 10% among girls. Smoking increased significantly with age (p<.0005). Susceptibility was more prevalent in rural areas than in urban areas (p<.05), but there were no urban-rural differences in lifetime, past 30-day smoking, or established smoking. Trend analyses revealed that smoking increased with age more rapidly among boys than among girls (p<.05). Smoking was more prevalent among rural boys than among urban boys, but it was more prevalent among urban girls than among rural girls (p<.05). CONCLUSIONS Adolescent smoking is a significant public health problem in China. Boys are at particularly high risk, as are girls living in urban areas. Effective smoking prevention programs for adolescents, as well as restrictions on tobacco industry marketing and youth access to tobacco, are needed to prevent tobacco-related morbidity and mortality in China.

Evidence for Joint Genetic Control of Insulin Sensitivity and Systolic Blood Pressure in Hispanic Families With a Hypertensive Proband

Background—The clustering of hypertension, insulin resistance, and obesity remains unexplained. We tested for genetic and nongenetic influences on the association among these traits in Hispanic families with hypertension. Methods and Results—Blood pressure and body mass index (BMI) were measured in 331 members of 73 Hispanic families in which an index case (proband) had hypertension. Insulin sensitivity (SI) was measured by euglycemic clamp in 287 probands and their spouses (parents’ generation) or their adult offspring. Correlation analysis examined relationships among traits within and between generations. Path analysis estimated genetic and nongenetic contributions to variability in systolic blood pressure (SBP), SI, and the correlation between them. In the offspring, there was a significant correlation between individuals for each trait, as well as significant correlations within and between individuals for all possible pairs of traits. Between generations, SBP, SI, and BMI in parents correlated with the same traits in their offspring; BMI in parents correlated with SI and SBP in offspring; and SI in parents correlated with SBP in offspring. Path analysis estimated that among offspring, genetic effects unrelated to BMI accounted for 60.8% of the variation in SBP, 36.8% of the variation in SI, and 31.5% of the correlation between SBP and SI after adjustment for age and sex. Heritable effects related to BMI accounted for an additional 14.0% of variation in SBP, 26.8% of variation in SI, and 56.3% of variation in their correlation. Conclusions—Clustering of hypertension and insulin resistance in Hispanic Americans is accounted for in part by heritable factors both associated with and independent of BMI.

Exploring Peers as a Mediator of the Association Between Depression and Smoking in Young Adolescents

Recent research has suggested that depression causes teens to begin smoking to elevate their mood. Other studies, however, have suggested the reverse causal direction: smoking causes depression. To gain a more complete understanding of the relationship between smoking and depression, potential mediators should be explored. This study explored how peer influences could mediate the relationship between depression and smoking. The methodology of Baron and Kenney was followed to test for mediation and moderation. Peers mediated the relationship between depression and smoking. Separate analyses by gender showed that depression remained significantly associated with smoking when peers were included in the model for girls only. Peer influence was related to depressed affect for both genders. These results provide evidence that peer influences are an important variable to take into consideration when addressing a depression smoking relationship.

The Influence of Depressive Symptoms on Experimental Smoking and Intention to Smoke in a Diverse Youth Sample

Numerous studies have shown associations between smoking and depression, but the generalizability of the relationship across ethnic groups remains unknown. The present study assessed the association between depression and smoking intention and experimentation among adolescents from four ethnic groups in the Los Angeles area-Chinese/Chinese American, Latino/Hispanic, Persian/Iranian, and White. Over 800 7th graders in the Los Angeles area completed measures of depressive symptoms, experimentation with smoking, intention to smoke, and sociodemographic covariates. Chinese/Chinese American students had the lowest levels of depressive symptoms, whereas Latinos/Hispanics had the highest levels. Latinos/Hispanics also were the most likely to intend to smoke in the next year and were the most likely to have started experimenting with cigarette smoking. Depressive symptoms were significantly associated with intention to smoke even after controlling for language use acculturation, socioeconomic status, gender, and ethnicity. The association between depressive symptoms and intention to smoke did not vary significantly across ethnic groups. These results indicate that the association between depressive symptoms and adolescent smoking generalizes across diverse ethnic groups.