Relationship between diabetes risk and admixture in postmenopausal African-American and Hispanic-American women

Energy-Adjusted Dietary Inflammatory Index and Diabetes Risk in Postmenopausal Hispanic Women

BACKGROUND

Type 2 diabetes is a major public health concern in the United States and worldwide. The dietary inflammatory index (DII) and the energy-adjusted DII (E-DII) are tools that assess dietary inflammation. Previous evidence suggests that obesity can modify the association between inflammation and disease.

OBJECTIVE

The aim of this study was to evaluate the association between the DII/E-DII and incident diabetes in self-identified Hispanic women from the Women's Health Initiative (WHI). The secondary aim was to evaluate whether obesity modifies the association between the DII/E-DII scores and incident diabetes.

DESIGN

Participants were from the WHI Observational Study and the Clinical Trial Components (except women from the treatment arm in the Dietary Modification Trial) conducted among postmenopausal women in the United States. DII/E-DII scores were calculated from a self-administered food frequency questionnaire at baseline that included 122 food items, of which 12 are representative of Hispanic eating patterns.

PARTICIPANTS/SETTINGS

Participants included 3,849 postmenopausal women who self-identified as Hispanic that were recruited for the WHI from 1993 to 1998 at 40 US clinical centers.

MAIN OUTCOME MEASURES

The outcome was incident diabetes.

STATISTICAL ANALYSIS PERFORMED

Cox regression models were used to assess the association between DII/E-DII and incident diabetes. Models were adjusted for age at baseline, lifestyle-related risk factors, known type 2 diabetes mellitus (T2DM) risk factors, and neighborhood socioeconomic status. Interaction was tested between the DII/E-DII scores and obesity.

RESULTS

The incidence of diabetes was 13.1% after a median follow-up of 13 years. Higher E-DII scores were associated with a higher risk of incident diabetes (hazard ratio [HR], 1.09; 95% confidence interval [CI], 1.04-1.14). There was no interaction between E-DII scores and obesity (P = 0.73).

CONCLUSIONS

Pro-inflammatory diets, as measured by higher E-DII scores, were associated with a higher risk of incident diabetes. Future research is needed for understanding how the inflammatory potential of diets can be decreased.

Dietary inflammatory index and cardiovascular disease risk in Hispanic women from the Women's Health Initiative

BACKGROUND

To evaluate the association between the dietary inflammatory index (DII^®) and incident cardiovascular disease (CVD) in Hispanic women from the Women's Health Initiative (WHI), and to determine if body mass index (BMI) interacted with the DII scores.

METHODS

Secondary analysis of baseline dietary data and long-term CVD outcomes among 3,469 postmenopausal women who self-identified as Hispanic enrolled in WHI. DII scores were calculated from self-administered food frequency questionnaires. The CVD outcomes included coronary heart disease (CHD) and stroke. Stratified Cox regression models were used to assess the relationship between DII scores and CVD in women with and without obesity. Models were adjusted for age, lifestyle risk factors, known risk factors, and neighborhood socioeconomic status.

RESULTS

The incidence of CHD was 3.4 and 2.8% for stroke after a median follow-up of 12.9 years. None of the DIIs were associated with CVD risk in this sample of Hispanic women. BMI interacted with the DII (p < 0.20) and stratified models showed that the associations between the DII and CVD were only significant in women with overweight (p < 0.05). In this group, higher DII scores were associated with a higher risk of CHD (HR 1.27; 95% CI: 1.08, 1.51) and a higher risk of stroke (HR 1.32; 95% CI: 1.07, 1.64).

CONCLUSION

Among postmenopausal Hispanic women with overweight, greater adherence to pro-inflammatory diets was associated with higher risk of CVD. Additional research is needed to understand how to promote long-term heart-healthy dietary habits to reduce inflammation and prevent CVD in at-risk Hispanic women.

Genetic admixture and cardiovascular disease risk in postmenopausal Hispanic women

BACKGROUND

Hispanics are a heterogeneous population with differences in the prevalence of cardiovascular disease (CVD) and its related risk factors among ethnic sub-groups. This study evaluated the association of genetic admixture and CVD in self-identified Hispanic women from the Women's Health Initiative (WHI).

METHODS

Data came from the WHI Observational Study and the Clinical Trial Components conducted among postmenopausal women. The CVD outcomes included coronary heart disease (CHD) and stroke. The proportions of European (EUR), sub-Saharan African (AFR), and Amerindian (AMI) admixture were estimated using 92 ancestry-informative markers. Cox regression models were used to assess the relationship between genetic admixture and CVD adjusting for age, lifestyle risk factors, known risk factors, and neighborhood socioeconomic status.

RESULTS

Among 5195 participants EUR ancestry was associated with a lower CHD risk after adjusting for age (HR 0.41, p = 0.02), and in the fully adjusted model (HR 0.40, p = 0.03). AFR ancestry was associated with a higher CHD risk after adjusting for age (HR 2.91, p = 0.03), but it only showed a trend in in the fully adjusted model (HR 2.46, p = 0.10). AMI ancestry was not statistically significantly associated with CHD and none of the genetic admixture proportions were statistically significantly associated with stroke (p > 0.05).

CONCLUSION

EUR ancestry was associated with a lower risk of CHD in Hispanic women. This highlights the need to account for genetic admixture in future CVD studies to consider different heritage groups to understand the role that genetic, neighborhood socioeconomic status, and environmental factors contribute to CVD health disparities in Hispanic women.

Type 2 diabetes risks and determinants in second-generation migrants and mixed ethnicity people of South Asian and African Caribbean descent in the UK

AIMS/HYPOTHESIS

Excess risks of type 2 diabetes in UK South Asians (SA) and African Caribbeans (AC) compared with Europeans remain unexplained. We studied risks and determinants of type 2 diabetes in first- and second-generation (born in the UK) migrants, and in those of mixed ethnicity.

METHODS

Data from the UK Biobank, a population-based cohort of ~500,000 participants aged 40-69 at recruitment, were used. Type 2 diabetes was assigned using self-report and HbA1c. Ethnicity was both self-reported and genetically assigned using admixture level scores. European, mixed European/South Asian (MixESA), mixed European/African Caribbean (MixEAC), SA and AC groups were analysed, matched for age and sex to enable comparison. In the frames of this cross-sectional study, we compared type 2 diabetes in second- vs first-generation migrants, and mixed ethnicity vs non-mixed groups. Risks and explanations were analysed using logistic regression and mediation analysis, respectively.

RESULTS

Type 2 diabetes prevalence was markedly elevated in SA (599/3317 = 18%) and AC (534/4180 = 13%) compared with Europeans (140/3324 = 4%). Prevalence was lower in second- vs first-generation SA (124/1115 = 11% vs 155/1115 = 14%) and AC (163/2200 = 7% vs 227/2200 = 10%). Favourable adiposity (i.e. lower waist/hip ratio or BMI) contributed to lower risk in second-generation migrants. Type 2 diabetes in mixed populations (MixESA: 52/831 = 6%, MixEAC: 70/1045 = 7%) was lower than in comparator ethnic groups (SA: 18%, AC: 13%) and higher than in Europeans (4%). Greater socioeconomic deprivation accounted for 17% and 42% of the excess type 2 diabetes risk in MixESA and MixEAC compared with Europeans, respectively. Replacing self-reported with genetically assigned ethnicity corroborated the mixed ethnicity analysis.

CONCLUSIONS/INTERPRETATION

Type 2 diabetes risks in second-generation SA and AC migrants are a fifth lower than in first-generation migrants. Mixed ethnicity risks were markedly lower than SA and AC groups, though remaining higher than in Europeans. Distribution of environmental risk factors, largely obesity and socioeconomic status, appears to play a key role in accounting for ethnic differences in type 2 diabetes risk.

PM2.5 Associated With Gray Matter Atrophy Reflecting Increased Alzheimer Risk in Older Women

OBJECTIVE

To examine whether late-life exposure to PM2.5 (particulate matter with aerodynamic diameters <2.5 µm) contributes to progressive brain atrophy predictive of Alzheimer disease (AD) using a community-dwelling cohort of women (age 70-89 years) with up to 2 brain MRI scans (MRI-1, 2005-2006; MRI-2, 2010-2011).

METHODS

AD pattern similarity (AD-PS) scores, developed by supervised machine learning and validated with MRI data from the Alzheimer's Disease Neuroimaging Initiative, were used to capture high-dimensional gray matter atrophy in brain areas vulnerable to AD (e.g., amygdala, hippocampus, parahippocampal gyrus, thalamus, inferior temporal lobe areas, and midbrain). Using participants' addresses and air monitoring data, we implemented a spatiotemporal model to estimate 3-year average exposure to PM2.5 preceding MRI-1. General linear models were used to examine the association between PM2.5 and AD-PS scores (baseline and 5-year standardized change), accounting for potential confounders and white matter lesion volumes.

RESULTS

For 1,365 women 77.9 ± 3.7 years of age in 2005 to 2006, there was no association between PM2.5 and baseline AD-PS score in cross-sectional analyses (β = -0.004; 95% confidence interval [CI] -0.019 to 0.011). Longitudinally, each interquartile range increase of PM2.5 (2.82 µg/m3) was associated with increased AD-PS scores during the follow-up, equivalent to a 24% (hazard ratio 1.24, 95% CI 1.14-1.34) increase in AD risk over 5 years (n = 712, age 77.4 ± 3.5 years). This association remained after adjustment for sociodemographics, intracranial volume, lifestyle, clinical characteristics, and white matter lesions and was present with levels below US regulatory standards (<12 µg/m3).

CONCLUSIONS

Late-life exposure to PM2.5 is associated with increased neuroanatomic risk of AD, which may not be explained by available indicators of cerebrovascular damage.

Outdoor air pollution exposure and inter-relation of global cognitive performance and emotional distress in older women

The interrelationships among long-term ambient air pollution exposure, emotional distress and cognitive decline in older adulthood remain unclear. Long-term exposure may impact cognitive performance and subsequently impact emotional health. Conversely, exposure may initially be associated with emotional distress followed by declines in cognitive performance. Here we tested the inter-relationship between global cognitive ability, emotional distress, and exposure to PM_2.5 (particulate matter with aerodynamic diameter <2.5 μm) and NO₂ (nitrogen dioxide) in 6118 older women (aged 70.6 ± 3.8 years) from the Women's Health Initiative Memory Study. Annual exposure to PM_2.5 (interquartile range [IQR] = 3.37 μg/m³) and NO₂ (IQR = 9.00 ppb) was estimated at the participant's residence using regionalized national universal kriging models and averaged over the 3-year period before the baseline assessment. Using structural equation mediation models, a latent factor capturing emotional distress was constructed using item-level data from the 6-item Center for Epidemiological Studies Depression Scale and the Short Form Health Survey Emotional Well-Being scale at baseline and one-year follow-up. Trajectories of global cognitive performance, assessed by the Modified-Mini Mental State Examination (3MS) annually up to 12 years, were estimated. All effects reported were adjusted for important confounders. Increases in PM_2.5 (β = -0.144 per IQR; 95% CI = -0.261; -0.028) and NO₂ (β = -0.157 per IQR; 95% CI = -0.291; -0.022) were associated with lower initial 3MS performance. Lower 3MS performance was associated with increased emotional distress (β = -0.008; 95% CI = -0.015; -0.002) over the subsequent year. Significant indirect effect of both exposures on increases in emotional distress mediated by exposure effects on worse global cognitive performance were present. No statistically significant indirect associations were found between exposures and 3MS trajectories putatively mediated by baseline emotional distress. Our study findings support cognitive aging processes as a mediator of the association between PM_2.5 and NO₂ exposure and emotional distress in later-life.

Leveraging genetic ancestry to study health disparities

Research to understand human genomic variation and its implications in health has great potential to contribute in the reduction of health disparities. Biological anthropology can play important roles in genomics and health disparities research using a biocultural approach. This paper argues that racial/ethnic categories should not be used as a surrogate for sociocultural factors or global genomic clusters in biomedical research or clinical settings, because of the high genetic heterogeneity that exists within traditional racial/ethnic groups. Genetic ancestry is used to show variation in ancestral genomic contributions to recently admixed populations in the United States, such as African Americans and Hispanic/Latino Americans. Genetic ancestry estimates are also used to examine the relationship between ancestry‐related biological and sociocultural factors affecting health disparities. To localize areas of genomes that contribute to health disparities, admixture mapping and genome‐wide association studies (GWAS) are often used. Recent GWAS have identified many genetic variants that are highly differentiated among human populations that are associated with disease risk. Some of these are population‐specific variants. Many of these variants may impact disease risk and help explain a portion of the difference in disease burden among racial/ethnic groups. Genetic ancestry is also of particular interest in precision medicine and disparities in drug efficacy and outcomes. By using genetic ancestry, we can learn about potential biological differences that may contribute to the heterogeneity observed across self‐reported racial groups.

Special Issue: Race reconciled II: Interpreting and communicating biological variation and race in 2021

Higher amounts of sedentary time are associated with short sleep duration and poor sleep quality in postmenopausal women

STUDY OBJECTIVES

To evaluate the associations between sedentary time, total (total-PA), light (light-PA), moderate (MOD-PA), and vigorous (VIG-PA) physical activity with indices of sleep in postmenopausal women.

METHODS

Baseline self-reported data from the Women's Health Initiative Observational Study (n = 75 074) were used in this cross-sectional analysis. Total-PA, light-PA, MOD-PA, and VIG-PA were categorized by metabolic equivalents of the activity (MET-hour [hr]/week [wk]) and were estimated using validated questionnaires. Sedentary time was categorized by hr/day and was estimated via questionnaire. Logistic regression was used to examine the associations between these variables and short sleep (≤6 hr/night), long sleep (≥10 hr/night), poor sleep quality, and insomnia symptoms after adjustment for age, race, socioeconomic status, body mass index, health status, depressive symptoms, smoking status, alcohol use, hormone therapy, and comorbidities.

RESULTS

Higher sedentary time (>11 hr/day) was associated with higher odds of short sleep (odds ratio [OR] = 1.80, 95% confidence interval [CI]: 1.72-1.88), poor sleep quality (OR = 1.85, 95% CI: 1.74-1.97), and insomnia symptoms (OR = 1.56, 95% CI: 1.49-1.64). Light-PA (>0 MET-hr/wk) was associated with lower odds of short sleep (OR = 0.96, 95% CI: 0.92-1.00), and higher amounts of total-PA (OR = 0.90, 95% CI: 0.84-0.97), light-PA (OR = 0.94, 95% CI: 0.89-1.00), and MOD-PA (OR = 0.91, 95% CI: 0.86-0.97) were associated with lower odds of poor sleep quality.

CONCLUSIONS

Our findings suggest that higher levels of light and moderate intensity physical activity are associated with better sleep quality, whereas higher amounts of sedentary time are associated with short sleep and lower quality sleep. Future studies should investigate the directionality of these associations and potential causal pathways.

Particulate matter and episodic memory decline mediated by early neuroanatomic biomarkers of Alzheimer's disease

Evidence suggests exposure to particulate matter with aerodynamic diameter <2.5 μm (PM2.5) may increase the risk for Alzheimer's disease and related dementias. Whether PM2.5 alters brain structure and accelerates the preclinical neuropsychological processes remains unknown. Early decline of episodic memory is detectable in preclinical Alzheimer's disease. Therefore, we conducted a longitudinal study to examine whether PM2.5 affects the episodic memory decline, and also explored the potential mediating role of increased neuroanatomic risk of Alzheimer's disease associated with exposure. Participants included older females (n = 998; aged 73-87) enrolled in both the Women's Health Initiative Study of Cognitive Aging and the Women's Health Initiative Memory Study of Magnetic Resonance Imaging, with annual (1999-2010) episodic memory assessment by the California Verbal Learning Test, including measures of immediate free recall/new learning (List A Trials 1-3; List B) and delayed free recall (short- and long-delay), and up to two brain scans (MRI-1: 2005-06; MRI-2: 2009-10). Subjects were assigned Alzheimer's disease pattern similarity scores (a brain-MRI measured neuroanatomical risk for Alzheimer's disease), developed by supervised machine learning and validated with data from the Alzheimer's Disease Neuroimaging Initiative. Based on residential histories and environmental data on air monitoring and simulated atmospheric chemistry, we used a spatiotemporal model to estimate 3-year average PM2.5 exposure preceding MRI-1. In multilevel structural equation models, PM2.5 was associated with greater declines in immediate recall and new learning, but no association was found with decline in delayed-recall or composite scores. For each interquartile increment (2.81 μg/m3) of PM2.5, the annual decline rate was significantly accelerated by 19.3% [95% confidence interval (CI) = 1.9% to 36.2%] for Trials 1-3 and 14.8% (4.4% to 24.9%) for List B performance, adjusting for multiple potential confounders. Long-term PM2.5 exposure was associated with increased Alzheimer's disease pattern similarity scores, which accounted for 22.6% (95% CI: 1% to 68.9%) and 10.7% (95% CI: 1.0% to 30.3%) of the total adverse PM2.5 effects on Trials 1-3 and List B, respectively. The observed associations remained after excluding incident cases of dementia and stroke during the follow-up, or further adjusting for small-vessel ischaemic disease volumes. Our findings illustrate the continuum of PM2.5 neurotoxicity that contributes to early decline of immediate free recall/new learning at the preclinical stage, which is mediated by progressive atrophy of grey matter indicative of increased Alzheimer's disease risk, independent of cerebrovascular damage.

Parsing the Paradox: Hispanic Mortality in the US by Detailed Cause of Death

US Hispanics are a disadvantaged population that paradoxically has lower mortality rates than non-Hispanic whites. We conducted a descriptive analysis of age-adjusted mortality rates for 113 causes of death for US Hispanics (USH) and US non-Hispanic whites (USNHW) during 1999-2015. All-cause, age-adjusted mortality rates per 100,000 were: 581.1 USH and 788.8 USNHW. Lower Hispanic mortality from cancer, heart disease, and respiratory disease accounted for almost all the all-cause mortality gap. USH rates were higher than USNHW rates for cancers of the stomach, liver, and cervix; diabetes mellitus; liver disease; and homicide. Behavioural factors such as less smoking among USH probably drive their lower rates for the major chronic diseases. Social disadvantages contribute to elevated risk for certain cancers, diabetes, and homicide. Efforts to improve Hispanic well-being in the US should remedy the social disadvantages while preserving the health advantages the population enjoys.

The Association between Prebiotic Fiber Supplement Use and Colorectal Cancer Risk and Mortality in the Women's Health Initiative

BACKGROUND

Fiber-based prebiotic supplements are marketed for maintaining bowel health and promoting beneficial gut bacteria. However, the association between prebiotic supplement use and colorectal cancer risk and mortality is unknown.

METHODS

The association between prebiotic use and colorectal cancer risk and mortality was evaluated in postmenopausal women in the Women's Health Initiative study. Self-reported prebiotic use was documented at study enrollment. Adjudicated colorectal cancer cases and mortality were captured using medical and death records. Cox proportional hazards models were used to estimate the HR related to prebiotic use and colorectal cancer risk and mortality.

RESULTS

In total, 3,032 colorectal cancer cases were diagnosed during an average 15.4 years of follow-up. Overall, 3.7% of women used a prebiotic with psyllium, the major fiber type. Use of any prebiotic supplement was not associated with colorectal cancer risk or mortality. The type of prebiotic supplement (none vs. insoluble or soluble) was not associated with colorectal cancer risk; however, use of insoluble fiber prebiotics compared with none was associated with higher colorectal cancer mortality [HR, 2.79; 95% confidence interval (CI), 1.32-5.90; P = 0.007]. Likelihood ratio tests indicated no significant interactions between prebiotic use and other colorectal cancer risk factors, including metabolic syndrome.

CONCLUSIONS

Prebiotic fiber supplement use was not associated with colorectal cancer risk. Insoluble, but not soluble, prebiotic fiber use was associated with higher colorectal cancer mortality. These findings do not support the promotion of prebiotic fiber supplements to reduce colorectal cancer risk or colorectal cancer mortality.

IMPACT

Further investigation is warranted for findings regarding insoluble prebiotic fiber and higher colorectal cancer mortality in postmenopausal women.

Associations between ACE-Inhibitors, Angiotensin Receptor Blockers, and Lean Body Mass in Community Dwelling Older Women

Studies suggest that ACE-inhibitors (ACE-I) and angiotensin receptor blockers (ARBs) may preserve skeletal muscle with aging. We evaluated longitudinal differences in lean body mass (LBM) among women diagnosed with hypertension and classified as ACE-I/ARB users and nonusers among Women's Health Initiative participants that received dual energy X-ray absorptiometry scans to estimate body composition (n=10,635) at baseline and at years 3 and 6 of follow-up. Of those, 2642 were treated for hypertension at baseline. Multivariate linear regression models, adjusted for relevant demographics, behaviors, and medications, assessed ACE-I/ARB use/nonuse and LBM associations at baseline, as well as change in LBM over 3 and 6 years. Although BMI did not differ by ACE-I/ARB use, LBM (%) was significantly higher in ACE-I/ARB users versus nonusers at baseline (52.2% versus 51.3%, resp., p=0.001). There was no association between ACE-I/ARB usage and change in LBM over time. Reasons for higher LBM with ACE-I/ARB use cross sectionally, but not longitundinally, are unclear and may reflect a threshold effect of these medications on LBM that is attenuated over time. Nevertheless, ACE-I/ARB use does not appear to negatively impact LBM in the long term.

Association between Dietary Energy Density and Obesity-Associated Cancer: Results from the Women's Health Initiative

BACKGROUND

Dietary energy density (DED) is the ratio of energy (kilocalories or kilojoules) intake to food weight (grams) and is a measure of diet quality. Consumption of foods high in DED has been associated with weight gain in adults.

OBJECTIVE

To investigate the association between baseline DED and incident obesity-associated cancers in the Women's Health Initiative.

DESIGN

Prospective cohort study of clinical trial and observational study participants.

PARTICIPANTS/SETTING

Postmenopausal women aged 50 to 79 years (N=92,295) enrolled in the observational study or the calcium and vitamin D trial and hormone replacement therapy trials of the Women's Health Initiative.

MAIN OUTCOME MEASURES

Incident, medical record-adjudicated, obesity-related cancers during follow-up. Exposure variable was DED (kilocalories per gram for the total diet) from self-reported dietary intake at baseline using a food frequency questionnaire.

STATISTICAL ANALYSES

The associations between DED and each incident cancer, or any obesity-related cancer, were examined using competing-risks regression models, with death as a competing risk. Body mass index-stratified models were generated to investigate body mass index as a potential modifying factor.

RESULTS

DED was associated with higher body mass index (28.9±6.0 vs 26.3±4.9) and waist circumference (89.3±14.2 vs 82.4±12.4 cm) for DED quintiles 5 vs 1, respectively. DED was associated with a 10% increased risk of any obesity-related cancer (subhazard ratio_{Q5 vs Q1}: 1.1, 95% CI 1.03 to 1.2; P=0.004). This increased risk appeared limited to women who were normal weight at enrollment.

CONCLUSIONS

Higher DED may be a contributing factor for obesity-related cancers, especially among normal-weight postmenopausal women and, as such, could serve as a modifiable behavior for dietary interventions to reduce obesity-associated cancer risk.

Association between Dietary Energy Density and Incident Type 2 Diabetes in the Women's Health Initiative

BACKGROUND

Dietary energy density, or energy available in relation to gram intake, can inform disease risk.

OBJECTIVE

The objective of this study was to investigate the association between baseline dietary energy density and risk of incident type 2 diabetes in postmenopausal women.

DESIGN

Dietary energy density, weight status, and type 2 diabetes incidence were prospectively characterized in a large cohort of postmenopausal women participating in one or more clinical trials or an observational study.

PARTICIPANTS/SETTING

The study involved 161,808 postmenopausal women recruited to the Women's Health Initiative observational study or clinical trials at 40 centers across the United States between 1993 and 1998.

MAIN OUTCOME MEASURES

The primary outcome was incident type 2 diabetes.

STATISTICAL ANALYSES PERFORMED

The association between dietary energy density quintiles and incident diabetes was tested using Cox proportional hazards regression.

RESULTS

A total of 143,204 participants without self-reported diabetes at enrollment completed baseline dietary assessment and were followed for 12.7±4.6 years. Risk of diabetes developing was 24% greater for women in the highest dietary energy density quintile compared with the lowest after adjusting for confounders (95% CI 1.17 to 1.32). Body mass index (calculated as kg/m2) and waist circumference mediated the relationship between dietary energy density and diabetes. In waist circumference-stratified analysis, women in dietary energy density quintiles 2 to 5 with waist circumferences >88 cm were at 9% to 12% greater risk of diabetes developing compared with women with waist circumference ≤88 cm.

CONCLUSIONS

In this prospective study, a higher baseline dietary energy density was associated with higher incidence of type 2 diabetes among postmenopausal women, both overall, and in women with elevated waist circumference.

Factors Associated With New-Onset Depression Following Ischemic Stroke: The Women's Health Initiative

BACKGROUND

Psychosocial characteristics have a strong effect on risk of depression, and their direct treatment with behavioral interventions reduces rates of depression. Because new-onset poststroke depression (NPSD) is frequent, devastating, and often treatment-resistant, novel preventive efforts are needed. As a first step toward developing behavioral interventions for NPSD, we investigated whether prestroke psychosocial factors influenced rates of NPSD in a manner similar to the general population.

METHODS AND RESULTS

Using the Women's Health Initiative, we analyzed 1424 respondents who were stroke-free at enrollment and had no self-reported history of depression from enrollment to their nonfatal ischemic stroke based on initiation of treatment for depression or the Burnam screening instrument for detecting depressive disorders. NPSD was assessed using the same method during the 5-year poststroke period. Logistic regression provided odds ratios of NPSD controlling for multiple covariates. NPSD occurred in 21.4% (305/1424) of the analytic cohort and varied by stroke severity as measured by the Glasgow scale, ranging from 16.7% of those with good recovery to 31.6% of those severely disabled. Women with total anterior circulation infarction had the highest level (31.4%) of NPSD while those with lacunar infarction had the lowest (16.1%). Prestroke psychosocial measures had different associations with NPSD depending on functional recovery of the individual.

CONCLUSIONS

There is a difference in the relationship of prestroke psychosocial status and risk of NPSD depending on stroke severity; thus it may be that the same preventive interventions might not work for all stroke patients. One size does not fit all.

Genetic ancestry in relation to the metabolic response to a US versus traditional Mexican diet: a randomized crossover feeding trial among women of Mexican descent

BACKGROUND/OBJECTIVES

Certain populations with a large proportion of indigenous American (IA) genetic ancestry may be evolutionarily adapted to traditional diets high in legumes and complex carbohydrates, and may have a detrimental metabolic response to US diets high in refined carbohydrates and added sugars. We tested whether IA ancestry modified the metabolic response to a US versus traditional Mexican diet in a controlled dietary intervention.

SUBJECTS/METHODS

First and second generation Mexican immigrant women (n=53) completed a randomized crossover feeding trial testing the effects of a US versus traditional Mexican diet. The metabolic response to the diets was measured by fasting serum concentrations of glucose, insulin, insulin-like growth factor-1 (IGF-1), IGF-binding protein-3 (IGFBP-3), adiponectin, C-reactive protein, interleukin-6 and computed homeostasis model assessment for insulin resistance (HOMA_IR). Blood collected at baseline was used for genotyping, and estimation of African, European and IA ancestries with the use of 214 ancestry informative markers.

RESULTS

The genetic ancestral background was 56% IA, 38% European and 6% African. Women in the highest IA ancestry tertile (>62%) were shorter in height, less educated and less acculturated to the US lifestyle, and tended to have higher waist-to-hip ratio compared with women in the middle and lowest IA ancestry tertiles, respectively. Compared with the US diet, the traditional Mexican diet tended to reduce glucose, insulin, IGF-1, IGFBP-3 and HOMA_IR among women in the middle IA ancestry group (IA ancestry ⩽45-62%), whereas having no effect on biomarkers related to inflammation.

CONCLUSIONS

We observed modest interactions between IA ancestry and the metabolic response to a US versus traditional Mexican diet among Mexican immigrant women.

Physical Activity Modifies the Association between Dietary Protein and Lean Mass of Postmenopausal Women

BACKGROUND

Maintenance of lean muscle mass and related strength is associated with lower risk for numerous chronic diseases of aging in women.

OBJECTIVE

Our aim was to evaluate whether the association between dietary protein and lean mass differs by physical activity level, amino acid composition, and body mass index categories.

DESIGN

We performed a cross-sectional analysis of a prospective cohort.

PARTICIPANTS/SETTING

Participants were postmenopausal women from the Women's Health Initiative with body composition measurements by dual-energy x-ray absorptiometry (n=8,298).

MAIN OUTCOME MEASURES

Our study measured percent lean mass, percent fat mass, and lean body mass index.

STATISTICAL ANALYSES PERFORMED

Linear regression models adjusted for scanner serial number, age, calibrated energy intake, race/ethnicity, neighborhood socioeconomic status, and recreational physical activity were used to determine the relationship between protein intake and body composition measures. Likelihood ratio tests and stratified analysis were used to investigate physical activity and body mass index as potential effect modifiers.

RESULTS

Biomarker-calibrated protein intake was positively associated with percent lean mass; women in the highest protein quintile had 6.3 percentage points higher lean mass than the lowest quintile (P<0.001). This difference rose to 8.5 percentage points for physically active women in the highest protein quintile (P_interaction=0.023). Percent fat mass and lean body mass index were both inversely related to protein intake (both P<0.001). Physical activity further reduced percent fat mass (P_interaction=0.022) and lean body mass index (P_interaction=0.011). Leucine intake was associated with lean mass, as were branched chain amino acids combined (both P<0.001), but not independent of total protein. All associations were observed for normal-weight, overweight, and obese women.

CONCLUSIONS

Protein consumption up to 2.02 g/kg body weight daily is positively associated with lean mass in postmenopausal women. Importantly, those that also engage in physical activity have the highest lean mass across body mass index categories.

Vegetable protein intake is associated with lower gallbladder disease risk: Findings from the Women's Health Initiative prospective cohort

OBJECTIVE

This study aimed to measure associations between gallbladder disease and protein intake patterns, separated by quantity and type (vegetable vs. animal), among postmenopausal women.

METHODS

Analyses were based on 130,859 postmenopausal women enrolled from 1993 to 1998 at 40 U.S. clinical centers in the Women's Health Initiative clinical trials and observational study. Women were excluded if they reported a history of gallbladder disease prior to baseline. Cox proportional hazards regression models, adjusted for gallbladder disease risk factors, were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between energy-adjusted protein intake and gallbladder disease.

RESULTS

In this study sample, 8.1% of postmenopausal women self-reported incident gallbladder disease. In multivariate analysis, women in the highest quintile of energy-adjusted vegetable protein intake (>24.0g/d) had a lower risk of gallbladder disease (HR, 0.87; 95% CI, 0.81-0.93) as compared to women in the lowest quintile (<16.3g/d) (Ptrend<0.001). Total protein intake was modestly protective against gallbladder disease (Ptrend<0.021). Animal protein intake was not associated with gallbladder disease risk. The protective effect of vegetable protein held stable only for women without history of diabetes (HR, 0.86; 95% CI, 0.80-0.92) and without recent weight loss (HR, 0.88; 95% CI, 0.80-0.97).

CONCLUSIONS

Vegetable protein intake is inversely associated with gallbladder disease risk in our sample of postmenopausal women. In addition to weight management, healthcare providers could emphasize vegetable protein as an additional dietary modality to promote lower risk for gallbladder disease.

Relative Contributions of Socioeconomic, Local Environmental, Psychosocial, Lifestyle/Behavioral, Biophysiological, and Ancestral Factors to Racial/Ethnic Disparities in Type 2 Diabetes

OBJECTIVE

Racial/ethnic minorities in the U.S. have a higher prevalence of type 2 diabetes mellitus (T2DM) than white adults. While many independent risk factors for T2DM have been identified, these determinants are often viewed in isolation without considering the joint contributions of competing risk factors. The objective of this study was to assess the relative contributions of six domains of influence to racial/ethnic disparities in T2DM.

RESEARCH DESIGN AND METHODS

Cross-sectional analyses were conducted using the Boston Area Community Health III Survey (2010-2012), the third wave of a population-based sample of men and women from three racial/ethnic groups (black, Hispanic, white) living in Boston, Massachusetts (N = 2,764). Prevalent diabetes was defined by self-report of T2DM, fasting glucose >125 mg/dL, or HbA1c ≥6.5%. Structural equation models were constructed to evaluate the direct effects of each conceptual domain of influence on T2DM prevalence, as well as their indirect effects on the race/ethnicity-T2DM relationship. All direct and indirect pathways were included.

RESULTS

The final model indicated that 38.9% and 21.8% of the total effect of black race and Hispanic ethnicity, respectively, on T2DM prevalence was mediated by the socioeconomic, environmental, psychosocial, and lifestyle/behavioral risk scores. The largest mediating influence was the socioeconomic risk score, which explained 21.8% and 26.2% of the total effect of black race and Hispanic ethnicity, respectively.

CONCLUSIONS

Our study found that socioeconomic factors had the greatest impact on explaining the excess prevalence of T2DM among racial/ethnic minorities.

Biogeographic ancestry is associated with higher total body adiposity among African-American females: the Boston Area Community Health Survey

OBJECTIVES

The prevalence of obesity is disproportionately higher among African-Americans and Hispanics as compared to whites. We investigated the role of biogeographic ancestry (BGA) on adiposity and changes in adiposity in the Boston Area Community Health Survey.

METHODS

We evaluated associations between BGA, assessed via Ancestry Informative Markers, and adiposity (body mass index (BMI), percent body fat (PBF), and waist-to-hip ratio (WHR)) and changes in adiposity over 7 years for BMI and WHR and 2.5 years for PBF, per 10% greater proportion of BGA using multivariable linear regression. We also examined effect-modification by demographic and socio-behavioral variables.

RESULTS

We observed positive associations between West-African ancestry and cross-sectional BMI (percent difference=0.62%; 95% CI: 0.04%, 1.20%), and PBF (β=0.35; 95% CI: 0.11, 0.58). We also observed significant effect-modification of the association between West-African ancestry and BMI by gender (p-interaction: <0.002) with a substantially greater association in women. We observed no main associations between Native-American ancestry and adiposity but observed significant effect-modification of the association with BMI by diet (p-interaction: <0.003) with inverse associations among participants with higher Healthy Eating Scores. No associations were observed between BGA and changes in adiposity over time.

CONCLUSION

Findings support that West-African ancestry may contribute to high prevalence of total body adiposity among African-Americans, particularly African-American women.

Relationship of pain and ancestry in African American women

BACKGROUND

African Americans are reported to be more sensitive to pain than European Americans. Pain sensitivity has been shown to be genetically linked in animal models and is likely to be in humans.

METHODS

Exactly, 11,239 self-identified African American post-menopausal women enrolled in the Women's Health Initiative had percentage African ancestry determined by ancestry informative markers, "Pain Construct" measurements and covariate information. They answered five questions about specific types and location of pain, such as joint, neck, low back, headache and urinary. They also answered two questions which were used to derive a "Pain Construct", a measure of general pain scored on a scale of 1-100. Associations were tested in linear regression models adjusting for age, self-reported medical conditions, neighbourhood socio-economic status, education and depression.

RESULTS

In the unadjusted model of the five specific types of pain measures, greater pain perception was associated with a higher proportion of African ancestry. However, some of the specific types of pain measures were no longer associated with African ancestry after adjustment for other study covariates. The Pain Construct was statistically significantly associated with African ancestry in both the unadjusted [β = -0.132, 95% confidence interval (CI) = -099 to -0.164; r = -0.075, 95% CI -0.056 to -0.093] and the adjusted models (β = -0.069 95% CI = -0.04 to -0.10).

CONCLUSIONS

Greater African ancestry was associated with higher levels of self-reported pain, although this accounted for only a minor fraction of the overall variation in the Pain Construct.

The contribution of biogeographical ancestry and socioeconomic status to racial/ethnic disparities in type 2 diabetes mellitus: results from the Boston Area Community Health Survey

PURPOSE

Racial/ethnic disparities in the incidence of type 2 diabetes mellitus (T2DM) are well documented, and many researchers have proposed that biogeographical ancestry (BGA) may play a role in these disparities. However, studies examining the role of BGA on T2DM have produced mixed results to date. Therefore, the objective of this research was to quantify the contribution of BGA to racial/ethnic disparities in T2DM incidence controlling for the mediating influences of socioeconomic factors.

METHODS

We analyzed data from the Boston Area Community Health Survey, a prospective cohort with approximately equal numbers of black, Hispanic, and white participants. We used 63 ancestry-informative markers to calculate the percentages of participants with West African and Native American ancestry. We used logistic regression with G-computation to analyze the contribution of BGA and socioeconomic factors to racial/ethnic disparities in T2DM incidence.

RESULTS

We found that socioeconomic factors accounted for 44.7% of the total effect of T2DM attributed to black race and 54.9% of the effect attributed to Hispanic ethnicity. We found that BGA had almost no direct association with T2DM and was almost entirely mediated by self-identified race/ethnicity and socioeconomic factors.

CONCLUSIONS

It is likely that nongenetic factors, specifically socioeconomic factors, account for much of the reported racial/ethnic disparities in T2DM incidence.

Relationship between glaucoma and admixture in postmenopausal African American women

OBJECTIVE

To investigate the association between African admixture and glaucoma prevalence among African American women.

DESIGN, SETTING, PARTICIPANTS

Participants included 11616 African American women from the Women's Health Initiative Study (WHI) for whom admixture information was available and included 2548 who self-reported a diagnosis of glaucoma.

MAIN OUTCOME MEASURES

Glaucoma.

RESULTS

Significant association was observed between self-identified glaucoma status and admixture. However, this association was not significant in a model that included neighborhood socioeconomic status (NSES), hypertension, diabetes and body mass index (BMI). Self-identified glaucoma status was associated with diabetes that persisted after adjustment for admixture, NSES, hypertension, and BMI. Lower NSES was also associated with higher glaucoma risk but this association was marginal in the fully adjusted model and neither hypertension nor BMI showed association. When glaucoma status was limited to those reporting use or no use of appropriate ophthalmologic medication, no associations were observed in any of the models.

CONCLUSION

This study failed to find an independent association of glaucoma status and African admixture and these findings suggest that the higher frequency glaucoma in African Americans may be largely due to other factors.

Genetic admixture and obesity: recent perspectives and future applications

The process of the colonization of the New World that occurred centuries ago served as a natural experiment, creating unique combinations of genetic material in newly formed admixed populations. Through a genetic admixture approach, the identification and genotyping of ancestry informative markers have allowed for the estimation of proportions of ancestral parental populations among individuals in a sample. These admixture estimates have been used in different ways to understand the genetic contributions to individual variation in obesity and body composition parameters, particularly among diverse admixed groups known to differ in obesity prevalence within the United States. Although progress has been made through the use of genetic admixture approaches, further investigations are needed in order to explore the interaction of environmental factors with the degree of genetic ancestry in individuals. A challenge to confront at this time would be to further stratify and define environments in progressively more granular terms, including nutrients, muscle biology, stress responses at the cellular level, and the social and built environments.

Relationship between hysterectomy and admixture in African American women

OBJECTIVE

Most studies suggest that hysterectomies are more common in African American women than in other ethnic groups. To assess this ethnic surgical disparity in a novel way, our main goal was to determine whether admixture (the proportion of sub-Saharan African or European origin in individuals) is associated with hysterectomy frequency in African American women in the Women's Health Initiative.

STUDY DESIGN

In this retrospective study, we used ancestry informative single nucleotide polymorphisms to estimate admixture proportions in >10,000 African American women from the Women's Health Initiative. Logistic regression models were used to assess the association between admixture and self-reported history of hysterectomy with and without controls for relevant covariates. Multinomial logistic regression models were used to assess the association between admixture and self-reported age of hysterectomy. We also considered other potential risk factors (adiposity, hypertension, and education) for hysterectomy accounting for admixture.

RESULTS

African admixture was a strong risk factor after the adjustment for multiple covariates (odds ratio, 1.85; P < .0001). The admixture risk for hysterectomy was highest for those procedures that were performed in the 35-39 age range (odds ratio, 3.08; P < .0001) and least evident in oldest ages (≥45 years old). Our analyses also suggest that adiposity, hypertension, and education were associated independently with hysterectomy in this population group.

CONCLUSION

These results suggest that higher African admixture is associated with higher frequencies of hysterectomy and that genetic studies that specifically target African American women and diseases that are associated with hysterectomy may be especially useful in understanding the pathogenesis and underlying cause of this disparity in health outcome.

Determinants of racial/ethnic disparities in incidence of diabetes in postmenopausal women in the U.S.: The Women's Health Initiative 1993-2009

OBJECTIVE

To examine determinants of racial/ethnic differences in diabetes incidence among postmenopausal women participating in the Women's Health Initiative.

RESEARCH DESIGN AND METHODS

Data on race/ethnicity, baseline diabetes prevalence, and incident diabetes were obtained from 158,833 women recruited from 1993-1998 and followed through August 2009. The relationship between race/ethnicity, other potential risk factors, and the risk of incident diabetes was estimated using Cox proportional hazards models from which hazard ratios (HRs) and 95% CIs were computed.

RESULTS

Participants were aged 63 years on average at baseline. The racial/ethnic distribution was 84.1% non-Hispanic white, 9.2% non-Hispanic black, 4.1% Hispanic, and 2.6% Asian. After an average of 10.4 years of follow-up, compared with whites and adjusting for potential confounders, the HRs for incident diabetes were 1.55 for blacks (95% CI 1.47-1.63), 1.67 for Hispanics (1.54-1.81), and 1.86 for Asians (1.68-2.06). Whites, blacks, and Hispanics with all factors (i.e., weight, physical activity, dietary quality, and smoking) in the low-risk category had 60, 69, and 63% lower risk for incident diabetes. Although contributions of different risk factors varied slightly by race/ethnicity, most findings were similar across groups, and women who had both a healthy weight and were in the highest tertile of physical activity had less than one-third the risk of diabetes compared with obese and inactive women.

CONCLUSIONS

Despite large racial/ethnic differences in diabetes incidence, most variability could be attributed to lifestyle factors. Our findings show that the majority of diabetes cases are preventable, and risk reduction strategies can be effectively applied to all racial/ethnic groups.