Belinda L. Needham

Socioeconomic status, health behavior, and leukocyte telomere length in the National Health and Nutrition Examination Survey, 1999–2002

The purpose of this study was to examine the association between socioeconomic status (SES) and leukocyte telomere length (LTL) - a marker of cell aging that has been linked to stressful life circumstances - in a nationally representative, socioeconomically and ethnically diverse sample of US adults aged 20-84. Using data from the National Health and Nutrition Examination Survey (NHANES), 1999-2002, we found that respondents who completed less than a high school education had significantly shorter telomeres than those who graduated from college. Income was not associated with LTL. African-Americans had significantly longer telomeres than whites, but there were no significant racial/ethnic differences in the association between education and telomere length. Finally, we found that the association between education and LTL was partially mediated by smoking and body mass index but not by drinking or sedentary behavior.

Trajectories of change in obesity and symptoms of depression: the CARDIA study.

OBJECTIVES We investigated whether, over time, baseline obesity is associated with change in depressive symptoms or if baseline symptoms of depression are associated with change in body mass index (BMI) and waist circumference. METHODS We used latent growth curve modeling to examine data from years 5, 10, 15, and 20 of the Coronary Artery Risk Development in Young Adults study (n = 4643). We assessed depressive symptomatology with the Center for Epidemiological Studies Depression scale. RESULTS Respondents who started out with higher levels of depressive symptoms experienced a faster rate of increase in BMI (for Whites only) and waist circumference (for Blacks and Whites) over time than did those who reported fewer symptoms of depression in year 5. Initial BMI and waist circumference did not influence the rate of change in symptoms of depression over time. CONCLUSIONS Depressive symptomatology likely plays a role in the development of physical health problems, such as cardiovascular disease, through its association with increases in relative weight and abdominal obesity over time.

Socioeconomic status and cell aging in children.

Theory suggests that chronic stress associated with disadvantaged social status may lead to acceleration in the rate of decline in physiological functioning. The purpose of this study is to examine the association between parental socioeconomic status (SES) and leukocyte telomere length (LTL), a marker of cell aging, in children. We examined SES and LTL in 70 white and black US children aged 7-13 who participated in the community-based AMERICO (Admixture Mapping for Ethnic and Racial Insulin Complex Outcomes) study. LTL was assessed using the polymerase chain reaction (PCR) method. Parental education was positively associated with child LTL, net of controls for sex, age, race/ethnicity, and family income. Compared to children with at least one college-educated parent, children whose parents never attended college had telomeres shorter by 1,178 base pairs, which is roughly equivalent to 6 years of additional aging. Socioeconomic disparities in cell aging are evident in early life, long before the onset of age-related diseases.

Depression, anxiety and telomere length in young adults: evidence from the National Health and Nutrition Examination Survey

Telomere length has been hypothesized to be a marker of cumulative exposure to stress, and stress is an established cause of depression and anxiety disorders. The aim of this study was to examine the relationship between depression, anxiety and telomere length, and to assess whether this relationship is moderated by race/ethnicity, gender and/or antidepressant use. Data were from the 1999-2002 National Health and Nutrition Examination Survey. Telomere length was assessed using the quantitative PCR method of telomere length relative to standard reference DNA. Past-year major depression (MD), generalized anxiety disorder (GAD) and panic disorder (PD), as well as depressed affect and anxious affect, were assessed using the Composite International Diagnostic Inventory (N=1290). Multiple linear regression was used to assess the relationship between depression and anxiety disorders and telomere length. Among women, those with GAD or PD had shorter telomeres than those with no anxious affect (β: −0.07, P<0.01), but there was no relationship among men (β: 0.08, P>0.05). Among respondents currently taking an antidepressant, those with MD had shorter telomeres than those without (β: −0.26, P<0.05), but there was no association between MD and telomere length among those not using antidepressants (β: −0.00, P>0.05). Neither depressive nor anxiety disorders were directly associated with telomere length in young adults. There was suggestive evidence that pharmacologically treated MD is associated with shorter telomere length, likely reflecting the more severe nature of MD that has come to clinical attention.

Leukocyte telomere length and mortality in the National Health and Nutrition Examination Survey, 1999-2002.

Background: This study examined the association between leukocyte telomere length—a marker of cell aging—and mortality in a nationally representative sample of US adults ages 50–84 years. We also examined moderating effects of age, sex, race/ethnicity, and education. Methods: Data were from the National Health and Nutrition Examination Survey, 1999–2002 (n = 3,091). Cox proportional hazards regression was used to estimate the risk of all-cause and cause- specific mortality adjusting for sociodemographic characteristics, smoking, body mass index, and chronic conditions. Results: Eight hundred and seventy deaths occurred over an average of 9.5 years of follow-up. In the full sample, a decrease of 1 kilobase pair in telomere length at baseline was marginally associated with a 10% increased hazard of all-cause mortality (hazard ratio [HR]: 1.1, 95% confidence interval [CI]: 0.9, 1.4) and a 30% increased hazard of death due to diseases other than cardiovascular disease or cancer (HR: 1.3, 95% CI: 0.9, 1.9). Among African-American but not white or Mexican-American respondents, a decrease of 1 kilobase pair in telomere length at baseline was associated with a two-fold increased hazard of cardiovascular mortality (HR: 2.0, 95% CI: 1.3, 3.1). There was no association between telomere length and cancer mortality. Conclusions: The association between leukocyte telomere length and mortality differs by race/ethnicity and cause of death.

Adolescent depressive symptomatology and young adult educational attainment: an examination of gender differences.

PURPOSE To examine the association between depressive symptomatology during adolescence and educational attainment in young adulthood and to determine whether this association varies by gender. METHODS This study uses data from the first and third waves of the National Longitudinal Study of Adolescent Health (Add Health). Symptoms associated with depression are assessed at Wave 1 with the Center for Epidemiologic Studies Depression Scale (CES-D). Educational attainment is assessed at Wave 3. Measures include failure to complete high school and failure to enter college (among high school graduates). The analytic sample contains 14,232 respondents aged 11-21 years at Wave 1 and aged 18-28 years at Wave 3. Approximately half the sample is female. RESULTS Adjusting for individual and family-level characteristics, depressive symptomatology during adolescence is associated with increased odds of failure to complete high school, but only for girls. Among high school graduates of both genders, depressive symptomatology is associated with failure to enter college. CONCLUSIONS This study offers support for the hypothesis that mental health problems experienced early in the life course impair status attainment.

Neighborhood Environment and Body Mass Index Trajectories From Adolescence to Adulthood

OBJECTIVES To investigate whether neighborhood conditions during adolescence are associated with body mass index (BMI) extending into young adulthood. METHODS Latent growth curve modeling was used to examine BMI over three waves (1996, 2001, and 2008) of the National Longitudinal Study of Adolescent Health (n = 9,115). RESULTS Parental perceptions of neighborhood disorder and neighborhood structural disadvantage were positively associated with BMI at baseline. Although parental perceptions of disorder were not associated with the rate of change in BMI over time, neighborhood structural disadvantage was positively associated with the slope of BMI. Adolescents who lived in more disadvantaged neighborhoods not only had higher BMI at the beginning of the study, but they also gained weight at a faster rate than those who lived in more advantaged neighborhoods at the first wave of data collection. The data also revealed notable gender, racial, and ethnic subgroup variations in the relationship between neighborhood context and BMI. CONCLUSION The neighborhood environment during the critical period of adolescence appears to have a long-term effect on BMI in adulthood. Policy interventions focusing on the neighborhood environment may have far-reaching effects on adult health.

Soda and Cell Aging: Associations Between Sugar-Sweetened Beverage Consumption and Leukocyte Telomere Length in Healthy Adults From the National Health and Nutrition Examination Surveys

OBJECTIVES We tested whether leukocyte telomere length maintenance, which underlies healthy cellular aging, provides a link between sugar-sweetened beverage (SSB) consumption and the risk of cardiometabolic disease. METHODS We examined cross-sectional associations between the consumption of SSBs, diet soda, and fruit juice and telomere length in a nationally representative sample of healthy adults. The study population included 5309 US adults, aged 20 to 65 years, with no history of diabetes or cardiovascular disease, from the 1999 to 2002 National Health and Nutrition Examination Surveys. Leukocyte telomere length was assayed from DNA specimens. Diet was assessed using 24-hour dietary recalls. Associations were examined using multivariate linear regression for the outcome of log-transformed telomere length. RESULTS After adjustment for sociodemographic and health-related characteristics, sugar-sweetened soda consumption was associated with shorter telomeres (b = -0.010; 95% confidence interval [CI] = -0.020, -0.001; P = .04). Consumption of 100% fruit juice was marginally associated with longer telomeres (b = 0.016; 95% CI = -0.000, 0.033; P = .05). No significant associations were observed between consumption of diet sodas or noncarbonated SSBs and telomere length. CONCLUSIONS Regular consumption of sugar-sweetened sodas might influence metabolic disease development through accelerated cell aging.

Life course socioeconomic status and DNA methylation in genes related to stress reactivity and inflammation: The multi-ethnic study of atherosclerosis

Epigenetic changes, such as DNA methylation, have been hypothesized to provide a link between the social environment and disease development. The purpose of this study was to examine associations between life course measures of socioeconomic status (SES) and DNA methylation (DNAm) in 18 genes related to stress reactivity and inflammation using a multi-level modeling approach that treats DNAm measurements as repeat measures within an individual. DNAm and gene expression were assessed in purified monocytes for a random subsample of 1,264 non-Hispanic white, African-American, and Hispanic participants aged 55–94 from the Multi-Ethnic Study of Atherosclerosis (MESA). After correction for multiple testing, we found that low childhood SES was associated with DNAm in 3 stress-related genes (AVP, FKBP5, OXTR) and 2 inflammation-related genes (CCL1, CD1D), low adult SES was associated with DNAm in one stress-related gene (AVP) and 5 inflammation-related genes (CD1D, F8, KLRG1, NLRP12, TLR3), and social mobility was associated with DNAm in 3 stress-related genes (AVP, FKBP5, OXTR) and 7 inflammation-related genes (CCL1, CD1D, F8, KLRG1, NLRP12, PYDC1, TLR3). In general, low SES was associated with increased DNAm. Expression data was available for 7 genes that showed a significant relationship between SES and DNAm. In 5 of these 7 genes (CD1D, F8, FKBP5, KLRG1, NLRP12), DNAm was associated with gene expression for at least one transcript, providing evidence of the potential functional consequences of alterations in DNAm related to SES. The results of this study reflect the biological complexity of epigenetic data and underscore the need for multi-disciplinary approaches to study how DNAm may contribute to the social patterning of disease.

Associations of Cadmium and Lead Exposure With Leukocyte Telomere Length: Findings From National Health and Nutrition Examination Survey, 1999–2002

Cadmium and lead are ubiquitous environmental contaminants that might increase risks of cardiovascular disease and other aging-related diseases, but their relationships with leukocyte telomere length (LTL), a marker of cellular aging, are poorly understood. In experimental studies, they have been shown to induce telomere shortening, but no epidemiologic study to date has examined their associations with LTL in the general population. We examined associations of blood lead and cadmium (n = 6,796) and urine cadmium (n = 2,093) levels with LTL among a nationally representative sample of US adults from the National Health and Nutrition Examination Survey (1999-2002). The study population geometric mean concentrations were 1.67 µg/dL (95% confidence interval (CI): 1.63, 1.70) for blood lead, 0.44 µg/L (95% CI: 0.42, 0.47) for blood cadmium, and 0.28 µg/L (95% CI: 0.27, 0.30) for urine cadmium. After adjustment for potential confounders, the highest (versus lowest) quartiles of blood and urine cadmium were associated with -5.54% (95% CI: -8.70, -2.37) and -4.50% (95% CI: -8.79, -0.20) shorter LTLs, respectively, with evidence of dose-response relationship (P for trend < 0.05). There was no association between blood lead concentration and LTL. These findings provide further evidence of physiological impacts of cadmium at environmental levels and might provide insight into biological pathways underlying cadmium toxicity and chronic disease risks.