Resiliency and Barriers to Successful Aging Among Middle-Aged Mexican Immigrants Residing in a Rural Agricultural Community.

OBJECTIVES: The Latino population is one of the largest, most diverse, and fastest-growing demographic groups in the United States. Although Latinos enjoy longer life spans and reduced mortality risk relative to non-Hispanic Whites, they have higher rates of chronic health conditions such as diabetes and dementia and live more of their older years with poor health and disability. Such inequities point to the need for this research focused on examining resiliency strategies and barriers to successful aging among various U.S. Latino subgroups. METHODS: This qualitative study used thematic content analysis to examine resiliency strategies and barriers to successful aging among Mexican immigrant women (n = 40) residing in an underserved agricultural community and entering mid-life (mean = 49 years old). RESULTS: With regards to barriers to successful aging, 3 themes emerged: (1) stressful lifestyle in the United States compared to the participants' home countries; (2) stress from expectations at home; and (3) stress due to work and the various components around work. The following 4 resiliency strategies emerged: (1) family as a motivation for moving forward in life and focusing on the success of children; (2) having a positive mindset; (3) praying to God for strength to overcome obstacles; and (4) self-care. DISCUSSION: Despite experiencing barriers to successful aging, participants practice various resiliency strategies to age successfully. Because many of the barriers identified are related to poverty-related stressors, systemic solutions addressing the social determinants of health are needed.

Childhood Overweight and Obesity and Pubertal Onset Among Mexican-American Boys and Girls in the CHAMACOS Longitudinal Study.

Secular trends in earlier initiation of puberty have been observed in recent decades. One risk factor appears to be increases in adiposity, as measured by body mass index. This trend is particularly notable among Latino populations, who have higher rates of overweight/obesity compared with non-Latino White youth. Previous research has focused primarily on White girls, resulting in data gaps regarding male puberty and among potentially high-risk populations. Using data from the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study, we examined body mass index at age 5 years (2005-2006) and multiple markers of pubertal onset, assessed repeatedly and longitudinally at 7 in-person visits, starting at age 9 and continuing through age 14 (2009-2015), among 336 Mexican Americans in Salinas, California. We observed no associations among boys, but found significantly earlier thelarche in overweight (HR = 1.7, 95% CI: 1.1, 2.7) and obese girls (HR = 1.5, 95% CI: 1.0, 2.4), menarche in overweight girls (HR = 1.6; CI: 1.0, 2.4), and pubarche in obese girls (HR = 1.9; CI: 1.2, 3.0), compared with normal-weight girls. This study examined an understudied population and included key covariates, such as birth weight and early adverse events, which are typically omitted in studies.

Deportation Worry, Cardiovascular Disease Risk Factor Trajectories, and Incident Hypertension: A Community-Based Cohort Study.

Background Worry about deportation has been associated with cardiovascular disease risk factors in cross-sectional research. No research has evaluated this association longitudinally or examined the association between deportation worry and incident cardiovascular disease outcomes. Methods and Results We used data from an ongoing community-based cohort of 572 women primarily of Mexican origin. We estimated associations between self-reported deportation worry and: (1) trajectories of blood pressure, body mass index, and waist circumference with linear mixed models, and (2) incident hypertension with Cox proportional hazards models. Nearly half (48%) of women reported "a lot," 24% reported "moderate," and 28% reported "not too much" deportation worry. Higher worry at baseline was associated with nonlinear systolic blood pressure and mean arterial pressure trajectories. For example, compared with not too much worry, a lot of worry was associated with a faster initial increase (ß, interaction with linear year term: 4.10; 95% CI, 1.17-7.03) followed by a faster decrease in systolic blood pressure (ß, interaction with quadratic year term: -0.80; 95% CI, -1.55 to -0.06). There was weak evidence of an association between deportation worry and diastolic blood pressure and no association with body mass index, waist circumference, or pulse pressure trajectories. Among 408 women without baseline hypertension, reporting a lot (hazard ratio, 2.17; 95% CI, 1.15-4.10) and moderate deportation worry (hazard ratio, 2.48; 95% CI, 1.17-4.30) were each associated with greater risk of incident hypertension compared with reporting not too much worry. Conclusions Deportation worry may contribute to widening disparities in some cardiovascular disease risk factors and outcomes over time.

Age-Related Differences in miRNA Expression in Mexican-American Newborns and Children.

Epigenetic mechanisms have emerged as an important pathway through which environmental exposures can affect health through the regulation of gene expression without changes in DNA sequence: microRNAs (miRNAs) are short non-coding RNAs that target protein-coding mRNAs, leading to post-transcriptional repression. They are involved in important physiologic processes, but little is known about how miRNA expression may change with age in children. We used an nCounter miRNA assay to assess the expression of 43 miRNAs in buffy coat samples collected from newborns (n = 121) and 7-year-old (n = 142) children. We identified 36 miRNAs that were differentially expressed between newborns and 7-year-olds after controlling for blood cell composition. Using pathway analysis, we found that differentially expressed miRNAs targeted genes enriched for processes related to post-translational modifications, metabolism, and immune response. Our study found that unlike adults, where miRNA expression levels in peripheral blood may decrease with age, expression levels of most miRNAs increased from birth to mid-childhood. This may be reflective of the role miRNAs may play in the highly coordinated mechanisms regulating genes involved in children's development. Furthermore, it will be important to adjust for both age and blood cell composition in future pediatric studies of miRNA expression in blood.

PON1 DNA methylation and neurobehavior in Mexican-American children with prenatal organophosphate exposure.

PON1 is a multifunctional enzyme involved in oxidative stress and detoxification of some organophosphate (OP) pesticides. It has been associated with nervous system diseases like Alzheimer's disease, amyotrophic lateral sclerosis, Parkinson's disease, and autism. We previously found that PON1 susceptible genotypes were associated with lower IQ scores in children. Epigenetic marks, such as DNA methylation, can regulate gene expression. Yet, data on whether DNA methylation may influence the relationship between PON1 levels and neurobehavior are limited. In this study, we used Illumina 450K and EPIC BeadChip arrays to assess PON1 DNA methylation in blood specimens collected from children (n = 238) at birth (cord blood) and age 7 years and examined their relationship with cognitive outcomes. The Wechsler Intelligence Scale for Children was used to assess Full Scale IQ and four composite measures (Verbal Comprehension, Perceptual Reasoning, Working Memory, and Processing Speed Indexes) in 7-year-old children. We observed a consistent yet nonsignificant inverse relationship of methylation at several CpG sites close to the PON1 transcription start site with Full Scale IQ and other composite measures of cognition. We also found an inverse relationship between cord blood methylation at cg15887283 with working memory and a positive association of 7-year-old methylation at cg22798737 with processing speed, independent of OP exposure. However, none of the associations remained significant after accounting for multiple comparisons. This study provides some evidence of the role DNA methylation may play in the known relationship between PON1 and neurobehavior in children, however it appears to be only suggestive and warrants additional research.

Worry About Deportation and Cardiovascular Disease Risk Factors Among Adult Women: The Center for the Health Assessment of Mothers and Children of Salinas Study.

Background: U.S. Latinos report high levels of concern about deportation for themselves or others. No previous research has tested the link between worry about deportation and clinical measures of cardiovascular risk. Purpose: We estimate the associations between worry about deportation and clinically measured cardiovascular risk factors. Methods: Data come from the Center for the Health Assessment of Mothers and Children of Salinas study. The analytic sample includes 545 Mexican-origin women. Results: In multivariable models, reporting a lot of worry about deportation was significantly associated with greater body mass index, greater risk of obesity, larger waist circumference, and higher pulse pressure. Reporting moderate deportation worry was significantly associated with greater risk of overweight and higher systolic blood pressure. Significant associations between worry about deportation and greater body mass index, waist circumference, and pulse pressure, respectively, held after correcting for multiple testing at p < .05. Conclusions: Worry about deportation may be an important cardiovascular risk factor for ethnic minority populations in the USA.

Association of prenatal and childhood PBDE exposure with timing of puberty in boys and girls.

BACKGROUND: Polybrominated diphenyl ether (PBDE) flame retardants are endocrine-disrupting chemicals that exhibit estrogenic and androgenic properties and may affect pubertal timing. METHODS: Study subjects were participants between 1999 and 2013 in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS), a longitudinal cohort study of predominantly Mexican origin families in Northern California. We measured serum concentrations of four PBDEs (BDE-47, -99, -100, -153) in blood collected from mothers during pregnancy (N=263) and their children at age 9years (N=522). We determined timing of pubertal onset in 309 boys and 314 girls using clinical Tanner staging every 9months between 9 and 13years of age, and timing of menarche by self-report. We used Poisson regression for relative risk (RR) of earlier puberty and parametric survival analysis for time ratios (TR) of pubertal milestones. RESULTS: Prenatal concentrations of all 4 congeners and Æ©PBDEs were associated with later menarche in girls (RRearlier menarche=0.5, 95% confidence interval (CI): 0.3, 0.9 for Æ©PBDEs) but earlier pubic hair development in boys (RRearlier pubarche=2.0, 95% CI: 1.3, 3.3 for Æ©PBDEs). No associations were seen between prenatal exposure and girls' breast or pubic hair development or boys' genital development. Childhood PBDE exposure was not associated with any measure of pubertal timing, except for an association of BDE-153 with later menarche. CONCLUSIONS: We found that prenatal PBDE exposure was associated with later menarche in girls but earlier pubarche in boys, suggesting opposite pubertal effects in girls and boys.

Maternal Depression and Childhood Overweight in the CHAMACOS Study of Mexican-American Children.

Objective Although previous studies have examined the impact of maternal depression on child overweight and obesity, little is known about the relationship in Latino families, who suffer from high risks of depression and obesity. We prospectively investigated the association between depressive symptoms in women with young children and child overweight and obesity (overweight/obesity) at age 7 years among Latino families. Methods Participants included 332 singletons with anthropometric measures obtained at 7 years from the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study, a birth cohort study. Maternal depression was assessed using the Center for Epidemiologic Studies-Depression (CES-D) scale when the children were 1, 3.5, and 7 years. Overweight and obesity was measured by body mass index (kg/m(2)) at age 7 years. Results 63 % of women had CES-D scores consistent with depression in at least one of the 3 given assessments. Compared to children whose mothers were never depressed, children whose mothers were depressed at all three assessments had 2.4 times the adjusted odds of overweight/obesity at age 7 years (95 % CI 1.1-5.6). However, a single positive maternal depression screen was not associated with child overweight/obesity and there was no difference in the odds of overweight/obesity by the age of the child when maternal depression occurred. Conclusion Chronic maternal depression during a child's early life was associated with child overweight/obesity at 7 years. Addressing maternal depression is a critical component of comprehensive obesity prevention and treatment strategies for Latino children.

DNA methylation of LINE-1 and Alu repetitive elements in relation to sex hormones and pubertal timing in Mexican-American children.

BACKGROUND: The molecular mechanisms linking environmental exposures to earlier pubertal development are not well characterized. Epigenetics may play an important role, but data on the relationship between epigenetic marks and puberty, particularly in humans, is limited. METHODS: We used pyrosequencing to measure Alu and long interspersed nucleotide elements (LINE-1) methylation in DNA isolated from whole blood samples collected from newborns and 9-y-old children (n = 266). Tanner staging was completed six times between ages 9 and 12 y to determine pubertal status, and hormone levels were measured in 12-y-old boys. RESULTS: Among girls, we observed a suggestive trend of increased odds of breast and pubic hair development with higher Alu and LINE-1 methylation in 9-y-old blood, respectively. The strongest association identified was an inverse association of LINE-1 methylation in 9-y-old girls with odds of experiencing menarche by age 12 (OR (95% CI): 0.63 (0.46, 0.87); P = 0.005). We observed a consistent inverse relationship for Alu and LINE-1 methylation at 9 y with luteinizing hormone (LH), testosterone and follicle-stimulating hormone levels in boys but it was only significant between LINE-1 and LH. CONCLUSION: DNA methylation of Alu and LINE-1 may be involved in puberty initiation and development. This relationship should be confirmed in future studies.

Manganese in teeth and neurodevelopment in young Mexican-American children.

INTRODUCTION: Manganese (Mn) is an essential nutrient but higher exposure has been associated with poorer neurodevelopment in children. METHODS: We measured Mn levels in prenatal (Mnpre) (n=197) and postnatal (Mnpost) dentin (n=193) from children's shed teeth using laser ablation inductively coupled plasma mass spectroscopy and examined the relationship with children's scores on the Mental Development Index (MDI) and Psychomotor Development Index (PDI) on the Bayley Scales of Infant Development at 6, 12, and 24-months. We explored non-linear associations and interactions by sex, blood lead concentrations and maternal iron status during pregnancy. RESULTS: A two-fold increase of Mnpost levels in dentin was associated with small decreases in MDI at 6-months and 12-months of age. We also observed a non-linear relationship between Mnpost levels and PDI at 6-months. We found effect modification by sex for Mnpost levels and neurodevelopment at 6-months with stronger effects among girls for both MDI (-1.5 points; 95% Confidence Interval (CI): -2.4, -0.6) and PDI (-1.8 points; 95% CI: -3.3, -0.3). Girls whose mothers had lower hemoglobin levels experienced larger decreases in MDI and PDI associated with Mnpre levels than girls whose mothers had higher hemoglobin levels (pinteraction=0.007 and 0.09, respectively). We did not observe interactions with blood lead concentrations or any relationships with neurodevelopment at 24-months. CONCLUSIONS: Using Mn measurements in tooth dentin, a novel biomarker that provides prenatal and early postnatal levels, we observed negative transient associations between postnatal Mn levels and early neurodevelopment with effect modification by sex and interactions with prenatal hemoglobin.

Prenatal and postnatal manganese teeth levels and neurodevelopment at 7, 9, and 10.5 years in the CHAMACOS cohort.

BACKGROUND: Numerous cross-sectional studies of school-age children have observed that exposure to manganese (Mn) adversely affects neurodevelopment. However, few prospective studies have looked at the effects of both prenatal and postnatal Mn exposure on child neurodevelopment. METHODS: We measured Mn levels in prenatal and early postnatal dentine of shed teeth and examined their association with behavior, cognition, memory, and motor functioning in 248 children aged 7, 9, and/or 10.5 years living near agricultural fields treated with Mn-containing fungicides in California. We used generalized linear models and generalized additive models to test for linear and nonlinear associations, and generalized estimating equation models to assess longitudinal effects. RESULTS: We observed that higher prenatal and early postnatal Mn levels in dentine of deciduous teeth were adversely associated with behavioral outcomes, namely internalizing, externalizing, and hyperactivity problems, in boys and girls at 7 and 10.5 years. In contrast, higher Mn levels in prenatal and postnatal dentine were associated with better memory abilities at ages 9 and 10.5, and better cognitive and motor outcomes at ages 7 and 10.5 years, among boys only. Higher prenatal dentine Mn levels were also associated with poorer visuospatial memory outcomes at 9 years and worse cognitive scores at 7 and 10.5 years in children with higher prenatal lead levels (≥0.8 µg/dL). All these associations were linear and were consistent with findings from longitudinal analyses. CONCLUSIONS: We observed that higher prenatal and early postnatal Mn levels measured in dentine of deciduous teeth, a novel biomarker that provides reliable information on the developmental timing of exposures to Mn, were associated with poorer behavioral outcomes in school-age boys and girls and better motor function, memory, and/or cognitive abilities in school-age boys. Additional research is needed to understand the inconsistencies in the neurodevelopmental findings across studies and the degree to which differences may be associated with different Mn exposure pathways and biomarkers.

In utero and childhood polybrominated diphenyl ether (PBDE) exposures and neurodevelopment in the CHAMACOS study.

BACKGROUND: California children's exposures to polybrominated diphenyl ether flame retardants (PBDEs) are among the highest worldwide. PBDEs are known endocrine disruptors and neurotoxicants in animals. OBJECTIVE: Here we investigate the relation of in utero and child PBDE exposure to neurobehavioral development among participants in CHAMACOS (Center for the Health Assessment of Mothers and Children of Salinas), a California birth cohort. METHODS: We measured PBDEs in maternal prenatal and child serum samples and examined the association of PBDE concentrations with children's attention, motor functioning, and cognition at 5 (n = 310) and 7 years of age (n = 323). RESULTS: Maternal prenatal PBDE concentrations were associated with impaired attention as measured by a continuous performance task at 5 years and maternal report at 5 and 7 years of age, with poorer fine motor coordination-particularly in the nondominant-at both age points, and with decrements in Verbal and Full-Scale IQ at 7 years. PBDE concentrations in children 7 years of age were significantly or marginally associated with concurrent teacher reports of attention problems and decrements in Processing Speed, Perceptual Reasoning, Verbal Comprehension, and Full-Scale IQ. These associations were not altered by adjustment for birth weight, gestational age, or maternal thyroid hormone levels. CONCLUSIONS: Both prenatal and childhood PBDE exposures were associated with poorer attention, fine motor coordination, and cognition in the CHAMACOS cohort of school-age children. This study, the largest to date, contributes to growing evidence suggesting that PBDEs have adverse impacts on child neurobehavioral development.

Cholinesterase and paraoxonase (PON1) enzyme activities in Mexican-American mothers and children from an agricultural community.

Exposure to organophosphate and carbamate pesticides can lead to neurotoxic effects through inhibition of cholinesterase enzymes. The paraoxonase (PON1) enzyme can detoxify oxon derivatives of some organophosphates. Lower PON1, acetylcholinesterase, and butyrylcholinesterase activities have been reported in newborns relative to adults, suggesting increased susceptibility to organophosphate exposure in young children. We determined PON1, acetylcholinesterase, and butyrylcholinesterase activities in Mexican-American mothers and their 9-year-old children (n=202 pairs) living in an agricultural community. We used Wilcoxon signed-rank tests to compare enzymatic activities among mothers and their children, and analysis of variance to identify factors associated with enzyme activities. Substrate-specific PON1 activities were slightly lower in children than their mothers; however, these differences were only statistically significant for the paraoxon substrate. We observed significantly lower acetylcholinesterase but higher butyrylcholinesterase levels in children compared with their mothers. Mean butyrylcholinesterase levels were strongly associated with child obesity status (body mass index Z scores >95%). We observed highly significant correlations among mother-child pairs for each of the enzymatic activities analyzed; however, PON1 activities did not correlate with acetylcholinesterase or butyrylcholinesterase activities. Our findings suggest that by age 9 years, PON1 activities approach adult levels, and host factors including sex and obesity may affect key enzymes involved in pesticide metabolism.

Organophosphate pesticide exposure and attention in young Mexican-American children: the CHAMACOS study.

BACKGROUND: Exposure to organophosphate (OP) pesticides, well-known neurotoxicants, has been associated with neurobehavioral deficits in children. OBJECTIVES: We investigated whether OP exposure, as measured by urinary dialkyl phosphate (DAP) metabolites in pregnant women and their children, was associated with attention-related outcomes among Mexican-American children living in an agricultural region of California. METHODS: Children were assessed at ages 3.5 years (n = 331) and 5 years (n = 323). Mothers completed the Child Behavior Checklist (CBCL). We administered the NEPSY-II visual attention subtest to children at 3.5 years and Conners' Kiddie Continuous Performance Test (K-CPT) at 5 years. The K-CPT yielded a standardized attention deficit/hyperactivity disorder (ADHD) Confidence Index score. Psychometricians scored behavior of the 5-year-olds during testing using the Hillside Behavior Rating Scale. RESULTS: Prenatal DAPs (nanomoles per liter) were nonsignificantly associated with maternal report of attention problems and ADHD at age 3.5 years but were significantly related at age 5 years [CBCL attention problems: ß = 0.7 points; 95% confidence interval (CI), 0.2-1.2; ADHD: ß = 1.3; 95% CI, 0.4-2.1]. Prenatal DAPs were associated with scores on the K-CPT ADHD Confidence Index > 70th percentile [odds ratio (OR) = 5.1; 95% CI, 1.7-15.7] and with a composite ADHD indicator of the various measures (OR = 3.5; 95% CI, 1.1-10.7). Some outcomes exhibited evidence of effect modification by sex, with associations found only among boys. There was also limited evidence of associations between child DAPs and attention. CONCLUSIONS: In utero DAPs and, to a lesser extent, postnatal DAPs were associated adversely with attention as assessed by maternal report, psychometrician observation, and direct assessment. These associations were somewhat stronger at 5 years than at 3.5 years and were stronger in boys.