Annals of Epidemiology - Articles in Press

Management of Obesity in the National Health and Nutrition Examination Survey (NHANES), 2007–2008 - Corrected Proof

Nithushi R. Samaranayake, Kwok L. Ong, Raymond Y.H. Leung, Bernard M.Y. Cheung — 2012-02-03

Purpose: The prevalence of obesity has been increasing in the United States. We set out to investigate the use of pharmacologic and non-pharmacologic therapy for the treatment of obesity in recent years.Methods: We included 2630 men and 2702 women who took part in the National Health and Nutrition Examination Survey from 2007 to 2008. We analyzed their demographic and anthropometric data and their weight and drug history.Results: A total of 45.9% of men and 45.0% of women were candidates for treatment (body mass index ≥30 kg/m2, or ≥27 kg/m2 with risk factors). Among these participants, 85.1% considered themselves overweight, 90.1% would like to lose weight, 61.9% had dietary changes, 36.5% exercised, 3.7% took nonprescription drugs, and 2.2% took prescription drugs to control weight during the preceding year. During the preceding month, 0.5% and 0.1% of participants were taking phentermine and orlistat, respectively. There were no participants on sibutramine.Conclusions: Although obesity is highly prevalent, only a small percentage of obese Americans are on anti-obesity medication. The withdrawal of sibutramine would have minimal impact on the general population. There is a need for more lifestyle changes in the majority of obese individuals.

Do Medical Marijuana Laws Increase Marijuana Use? Replication Study and Extension - Corrected Proof

Sam Harper, Erin C. Strumpf, Jay S. Kaufman — 2012-01-30

Purpose: To replicate a prior study that found greater adolescent marijuana use in states that have passed medical marijuana laws (MMLs), and extend this analysis by accounting for confounding by unmeasured state characteristics and measurement error.Methods: We obtained state-level estimates of marijuana use from the 2002 through 2009 National Survey on Drug Use and Health. We used 2-sample t-tests and random-effects regression to replicate previous results. We used difference-in-differences regression models to estimate the causal effect of MMLs on marijuana use, and simulations to account for measurement error.Results: We replicated previously published results showing higher marijuana use in states with MMLs. Difference-in-differences estimates suggested that passing MMLs decreased past-month use among adolescents by 0.53 percentage points (95% confidence interval [CI], 0.03–1.02) and had no discernible effect on the perceived riskiness of monthly use. Models incorporating measurement error in the state estimates of marijuana use yielded little evidence that passing MMLs affects marijuana use.Conclusions: Accounting for confounding by unmeasured state characteristics and measurement error had an important effect on estimates of the impact of MMLs on marijuana use. We find limited evidence of causal effects of MMLs on measures of reported marijuana use.

Metabolic Syndrome and 16-Year Cognitive Decline in Community-Dwelling Older Adults - Corrected Proof

2012-01-30

Purpose: To determine whether metabolic syndrome is associated with accelerated cognitive decline in community-dwelling older adults.Methods: A longitudinal study of 993 adults (mean 66.8 ± 8.7 years) from the Rancho Bernardo Study. Metabolic syndrome components, defined by 2001 NCEP-ATP III criteria, were measured in 1984-1987. Cognitive function was first assessed in 1988-1992. Cognitive assessments were repeated approximately every 4 years, for a maximum 16-year follow-up. Mixed-effects models examined longitudinal rate of cognitive decline by metabolic syndrome status, controlling for factors plausibly associated with cognitive function (diabetes, inflammation).Results: Metabolic syndrome was more common in men than women (14% vs. 9%, p = .01). In women, metabolic syndrome was associated with greater executive function and long-term memory decline. These associations did not differ by inflammatory biomarker levels. Diabetes did not alter the association of metabolic syndrome with long-term recall but modified the association with executive function: metabolic syndrome was associated with accelerated executive function decline in diabetic women only. Metabolic syndrome was not related to rate of decline on any cognitive measure in men.Conclusions: Metabolic syndrome was a risk factor for accelerated cognitive decline, but only in women. Prevention of metabolic syndrome may aid in maintenance of cognitive function with age.

Differences in Preterm and Low Birth Weight Deliveries between Spanish and Immigrant Women: Influence of the Prenatal Care Received - Corrected Proof

2012-01-30

Objectives: To compare the risk of preterm and low birth weight among newborns from native and immigrant women and to assess the role of prenatal care in the association between the ethnic origin of the women and their reproductive outcomes.Methods: Cross-sectional study of 21,708 women giving birth between 1997 and 2008 in a region of Spain. Multinomial logistic regression models were adjusted to evaluate associations between mother’s area of origin and adverse reproductive outcomes and to assess the role of prenatal care in the occurrence of adverse reproductive results.Results: Our results indicate a worse prenatal control in immigrants than in natives. Very preterm birth (VPTB) and very low birth weight (VLBW) were greater among immigrants (odds ratio [OR], 1.78; 95% confidence interval [95% CI], 1.14−2.79 for VPTB and OR, 1.73; 95% CI, 0.89−3.33 for VLBW) but after adjustment for prenatal care the differences were substantially reduced (OR, 1.43; 95% CI 0.85−2.42 for VPTB and OR 1.15; 95% CI 0.53−2.52 for VLBW).Conclusions: Given the positive impact of prenatal care on reproductive results, strategies to improve it among immigrant women should be implemented. The difference found in the direction of the association between area of origin and different categories of low birth weight and preterm suggest that very and moderate categories should be analyzed separately in immigrant studies.

Life Course Variation in the Relation Between Maternal Marital Status and Preterm Birth - Corrected Proof

Abdulrahman M. El-Sayed, Melissa Tracy, Sandro Galea — 2012-01-30

Purpose: Maternal marriage is protective against preterm birth (PTB), whereas advanced maternal age is associated with increased PTB risk. Because relations between social factors and health may vary during the life course, we assessed how the relation between marital status and PTB risk may change with maternal age.Methods: We assessed the interaction between marital status and maternal age as a determinant of PTB among all live singleton births in Michigan between 1995 and 2006. We also fit stratified models by race. We calculated absolute differences in predicted PTB as well as odds ratios of PTB by marital status for each age group.Results: In adjusted models, there was a significant interaction (pinteraction<.001) between marital status and maternal age. The predicted probability of PTB by marital status was marginally different among mothers ages 20–25 years (absolute difference of 1.5%); this difference was substantially greater (3.9% or greater) after 31 years of age. Odds of PTB followed a similar trajectory. Findings were similar among black and white mothers.Conclusions: The relationship between marriage and PTB may vary with maternal age suggesting that the influence of social factors on risk for adverse birth outcomes may differ through the maternal life trajectory. We discuss plausible explanations for these findings.

Cancer Incidence, Mortality, and Blood Lead Levels Among Workers Exposed to Inorganic Lead - Corrected Proof

2012-01-30

Purpose: We aimed to measure mortality and cancer incidence in a cohort of lead-exposed workers by using blood lead levels to assess exposure.Methods: The cohort comprised male lead workers. Subjects were matched to cancer and death registries. Observed death and cancer incidence rates were compared with population rates to obtain standardized mortality ratios (SMR) and standardized incidence ratios (SIR).Results: There were 4114 male subjects with average follow-up time of 16.2 years, and 406 deaths were observed. There were significant results for overall death (SMR, 111; 95% confidence interval [95% CI], 101–123), digestive system deaths (SMR, 167; 95% CI, 110–250), and deaths from external causes (SMR, 135; 95% CI, 105–174). A total of 228 subjects had cancer, with an overall SIR of 83 (95% CI, 73–95); liver cancer SIR of 217 (95% CI, 103–454) and esophageal cancer SIR of 240 (95% CI, 129–447). The latter was seven-fold greater (SIR 755; 95% CI, 314–1813) among those with a blood lead level result above 30 μg/dL compared with population rates. No other increases in cancers were observed.Conclusions: Overall mortality was elevated. Although incidence rates of overall cancer were low, further studies and analysis are required to investigate any biologically plausible associations between inorganic lead and liver or esophageal cancer.

Educational Inequalities in Preterm and Term Small-for-Gestational-Age Birth Over Time - Corrected Proof

2012-01-30

Purpose: Time trends in educational inequalities in small-for-gestational-age (SGA) birth are important to evaluate for policy, especially at preterm gestational ages when morbidity and mortality are typically greater. We evaluated educational inequalities in preterm and term SGA birth over time, accounting for potential bias at preterm gestational ages.Methods: Data included 2,204,056 singleton live births from 25 to 43 gestational weeks, 1981 to 2007. We estimated prevalence ratios (PR) and percent prevalence differences (PPD) of preterm and term SGA birth for a continuous education score, accounting for maternal characteristics. Sensitivity analyses included correction for misclassification of preterm SGA status, and use of fetuses-at-risk denominators in regression models.Results: Although prevalence of SGA birth decreased over time, relative educational inequalities (PRs) persisted for preterm and term cases. PPDs decreased slightly, but more for term than preterm SGA birth. Sensitivity analyses indicated that PRs for education were stronger for preterm than term SGA birth. PPDs were larger for term SGA birth in the first period, but greater for preterm SGA birth in the last period.Conclusions: Relative educational inequalities in SGA birth persisted over time. The difference in prevalence between the least and most educated mothers is currently greater for preterm than for term SGA birth.

Parental Age and Autism Spectrum Disorders - Corrected Proof

2012-01-27

Purpose: We sought to study the possible association between parental age and autism spectrum disorder (ASD) by using both a cohort design and a sibling design.Methods: Our cohort included all singleton births in Denmark from January 1, 1980, through December 31, 2003, a total of 1,311,736 children. Cases of ASDs were obtained from the Danish National Psychiatric Register using International Classification of Diseases (ICD)-8 and ICD-10.Results: A total of 9556 children were diagnosed with an ASD. Both maternal and paternal age were associated with a greater risk of ASD in the offspring (hazard ratios ranging from 1.21 (1.10–1.34) to 1.65 (1.09–2.48) depending on combinations of parental age categories; <35, 35–39, and 40+ years). For mothers younger than 35 years, the risk of ASD increased with increasing father’s age group. For fathers younger than 35 years, the risk of ASD increased with increasing maternal age.Conclusions: We found an association between parental age and ASD in the cohort study, but the combined underlying mechanisms through which paternal and maternal age impact ASD risk do not seem to act synergistically. The results of the sibling analysis suggest that the association between parental age and ASD found in the cohort study cannot be accounted for by common genetic and environmental factors.

Temporal and Geographic Shifts in Urban and Nonurban Cocaine-Related Fatal Overdoses in British Columbia, Canada - Corrected Proof

Brandon D.L. Marshall, M.-J. Milloy, Evan Wood, Sandro Galea, Thomas Kerr — 2012-01-24

Purpose: Illicit drug overdose is a leading cause of premature mortality. We sought to examine fatal overdose trends from 2001 to 2005 in urban and nonurban areas of British Columbia, Canada.Methods: We conducted a review of all provincial coroner files in which drug overdose was the cause of death between January 1, 2001, and December 31, 2005. We compared cocaine and noncocaine-related overdoses and examined temporal changes in cocaine-related mortality rates in urban and nonurban areas. Multilevel mixed effects models were used to determine the independent risk factors for cocaine-related death. Spatial analyses were conducted to identify clusters of these cases.Results: During the study period, 904 illicit drug overdoses were recorded, including 369 (40.8%) in nonurban areas and 532 (58.9%) related to cocaine consumption. In a multilevel model, we observed a significant interaction (p = .010) between population density and year, indicating a considerable and differential increase in the likelihood of cocaine-related deaths in nonurban areas. Cocaine-related deaths were clustered in the southeast region of the province.Conclusions: Cocaine-related overdoses in nonurban areas should be a public health concern. Evidence-based interventions to reduce the risks associated with cocaine consumption and reach drug users in nonurban settings are needed.

Effect of Correcting for Long-Term Variation in Major Coronary Heart Disease Risk Factors: Relative Hazard Estimation and Risk Prediction in the Atherosclerosis Risk in Communities Study - Corrected Proof

2012-01-05

Purpose: To examine the effect of correcting coronary heart disease (CHD) risk factors for long-term within-person variation on CHD risk.Methods: By using 5533 men and 7301 women from the Atherosclerosis Risk in Communities (ARIC) study, we compared models incorporating risk factors measured at a single visit and models incorporating additional measurements for systolic blood pressure, total cholesterol, and high-density lipoprotein cholesterol taken 3 years before baseline.Results: The largest change away from null was observed for systolic blood pressure, ie, hazard ratio (HR) 1.38 to 1.69 (+81%) in women and HR 1.26 to 1.41 (+56%) in men. HRs also decreased for age (−32% in women, −9% in men), race (−67% in women), the presence of diabetes (−13% in men and women), and medication use for hypertension (−27% in women, −26% in men) and cholesterol (−97% in women, HR 1.06–0.93 in men). The area under the ROC curve did not improve significantly in men or women, whereas reclassification was only significant in women (net reclassification improvement 5.4%, p = 0.016).Conclusions: Modeling long-term variation in CHD risk factors had a substantial impact on HR estimates, with new effect estimates further from the null for some risk factors and closer for others including age and medication use, but only improved risk classification in women.

Bacterial Vaginosis, Gonorrhea, and Chlamydial Infection Among Women Attending a Sexually Transmitted Disease Clinic: A Longitudinal Analysis of Possible Causal Links - Corrected Proof

2011-12-22

Purpose: Interactions between bacterial vaginosis (BV) and inflammatory sexually transmitted infections, such as gonorrhea and chlamydial infection, are not well understood. Furthermore, evidence regarding the sexual transmission of BV is equivocal.Methods: We assessed associations between incident BV and incidences of gonorrhea and/or chlamydial infection (“gonorrhea/chlamydia”), as well as similarities in associations for the two processes, among 645 female patients at a sexually transmitted disease clinic in Alabama followed prospectively for 6 months from 1995 to 1998. We identified predictors of both incident BV and gonorrhea/chlamydia and used bivariate logistic regression to determine whether these predictors differed.Results: Participants completed 3188 monthly, follow-up visits. Several factors associated with incident BV involved sexual intercourse: young age (<16 years) at first intercourse (adjusted odds ratio [aOR], 1.5; 95% confidence interval [CI], 1.1–1.9), recent drug use during sex (aOR, 1.7; 95% CI, 1.2–2.5), prevalent trichomoniasis (aOR, 2.8; 95% CI, 1.7–4.6) and incident syphilis (aOR, 9.7; 95% CI, 1.9–48.4). Few statistical differences between potential factors for BV and gonorrhea/chlamydia emerged. BV appeared to precede the acquisition of gonorrhea/chlamydia (pairwise odds ratio, 1.6; 95% CI, 1.1–2.3), and vice versa (pairwise odds ratio, 2.4; 95% CI, 1.7–3.5).Conclusions: Findings are consistent with a causal role of sexual behavior in the acquisition of BV and confirm that BV facilitates acquisition of gonorrhea/chlamydia and vice versa independently from other risk factors.