Gender difference in "second-shift" physical activity: New insights from analyzing accelerometry data in a nationally representative sample.

The gendered organization of daily activities results in differential contexts of physical activity (PA) for the working population, especially during the "second shift" - a time window dominated by household-based activities. Existing research predominantly relies on self-reported leisure-time activities, yielding a partial understanding of gender difference in the source, timing, and accumulation pattern of PA. To address these limitations, this study draws on the interplay between work and family to understand how they shape gender difference in household-based PA across occupational groups. It combines work schedule and accelerometry PA data from the 2005-2006 National Health and Nutrition Examination Survey (NHANES), which permits our study of second-shift PA on workdays among full-time workers, aged 20 to 49, with a regular daytime schedule. To capture different aspects of second-shift PA, the PA outcomes are measured as both volume and accumulation patterns during time windows following (i.e., 6pm-9pm) and prior to typical working hours (7:30am-8:30am). Using generalized estimating equations, we estimate gender differences in the volume and fragmentation of second-shift PA. Overall, women with a full-time job exhibit both higher volume and higher fragmentation of second-shift PA than their male counterparts. The occupational group moderates such gender difference in PA. The gender gaps in PA volume and fragmentation are only evident for professional workers, whereas the second shift represents a gender-neutral context for PA accumulation for non-professional groups. These findings are supported by a secondary analysis when analyzing the whole-day PA data using functional data analysis. Such social patterning of second-shift PA calls for further research on gendered PA under the interplay of work and family beyond the usual focus on leisure activities.

Prospective Cohort Study of Emergency Department Visit Frequency and Diagnoses Before and During COVID-19 Pandemic in Urban, Low-Income, US- and Foreign-Born Mothers in Boston, MA.

Background: The coronavirus 2019 (COVID-19) pandemic fundamentally changed how populations interface with the healthcare system. Despite historical spikes in US mortality during the pandemic, emergency department (ED) visits were paradoxically low. This is a concerning phenomenon that raises a red flag regarding access to care, especially among vulnerable populations. In this study we sought to understand how ED utilization evolved during the COVID-19 pandemic among traditionally understudied, low-income, racially diverse US- and foreign-born mothers. Methods: This is a secondary analysis of a pre-existing dataset of 3,073 participants enrolled in the Boston Birth Cohort at birth and followed prospectively. We obtained ED visit diagnoses from 2019 and 2020 via electronic health records, categorized according to the International Classification of Diseases, 10th Revision, and compared them using graph plots, chi-square, and negative binomial regression. Results: The number of ED visits decreased by 29.1% (P < 0.001) from 2019 (1,376) to 2020 (976). However, visits for infectious and parasitic diseases, including COVID-19, increased by 90.6% (32:61) with COVID-19 accounting for 77% of those visits in 2020 (47/61). Mental health-related visits increased by 40.9% (44:62), with diagnoses of alcohol use disorder increasing by 183% (6:17). Regression analysis showed 50% less ED utilization among foreign- vs US-born participants; however, the increase in infectious diseases visits was greater among foreign-born compared to US-born mothers (185% vs 26%, P = 0.01), while the increase in mental health diagnoses was greater among US-born mothers (69% vs -33%, P = 0.10). Conclusion: Despite a decrease in total ED visits during the pandemic, there was an increase in COVID-19- (immigrant > US born) and mental health- (US-born only) related visits. Our findings demonstrate that EDs remain a critical access point for care for minority populations and have implications for preparedness, resources, and services of EDs in urban settings to better address the needs of communities. However, alternative avenues for healthcare services for these populations, particularly during health crises, warrant further investigation.

Occupational determinants of physical activity at work: Evidence from wearable accelerometer in 2005-2006 NHANES.

Occupation determines workers' physical activity (PA) in the workplace, an important health behavior contributing to health outcomes. However, self-reported measure limits our understanding of how occupational tasks differentiate workers' PA in terms of the type, frequency, intensity, and duration. In addition, accurate estimation of occupation-based PA during workers' actual working hours requires precise work schedule information. To address these limitations, this study employs data on accelerometer-monitored PA and work schedule from the 2005-2006 National Health and Nutrition Examination Survey (NHANES). It asks two questions: How do occupations determine PA among regular daytime workers in the United States? Second, how large a share of PA difference between two occupations is attributable to differences in the implicit occupational tasks, relative to workers' demographic, health preconditions, and socioeconomic attributes? Calculating PA during the 9-to-5 period among daytime regular workers on weekdays and conducting Blinder-Oaxaca decomposition analysis, we yield insights into the occupational determinant of both PA volume (total activity counts) and fragmentation (bouts of activities). Worksite health promotion can utilize the objective occupation-PA link and design occupation-tailored interventions, which is currently underdeveloped in the United States. Moreover, our findings shed light on the physical nature of occupation, suggesting a fruitful step to reconcile the documented mixed findings on occupation-based PA and health outcomes in future studies.

Residential racial segregation and social distancing in the United States during COVID-19.

BACKGROUND: Our objective is to examine whether residential racial segregation may be constraining capacities for social distancing thus leaving African Americans potentially more exposed to contracting COVID-19. We hypothesized that residential racial segregation constrains African Americans' spatial mobility when the whole population is locked down but increases their need for moving under reopening orders. METHODS: We employ a Black/White dissimilarity index as our independent variable and county-level mobility ratios as our dependent variable. Using generalized estimating equations for longitudinal data, we analyzed the effects of Black/White segregation on population mobility by counties across the United States from March 8 to August 7, 2020 under two different COVID-19 related policy conditions: lockdown and reopening. FINDINGS: While higher county-wide levels of segregation were significantly associated with decreased mobility under lockdown and stay-at-home orders, we found that this relationship between segregation and mobility dissipated under reopening orders. INTERPRETATIONS: Investigating the effects of health policy without considering differing effects due to structural racism will likely ignore complexities that may create unintended consequences of health policy. Our conclusions suggest African Americans may face structural limitations to effective social distancing as evidenced by higher rates of mobility after reopening policies go into effect.

Adolescents' Patterns of Well-Care Use Over Time: Who Stays Connected.

INTRODUCTION: Well-care use can positively impact adolescents' current and future health. Understanding adolescents' longitudinal well-care use is critical to determine to whom and when to target engagement strategies to improve healthcare access. This study describes prospective well-care use patterns from childhood through adolescence stratified by sex. METHODS: The sample (N=6,872) was drawn from the Child/Young Adult component of the household-based 1979 National Longitudinal Survey of Youth consisting of biological children born to female respondents (1980-1997). Well-care use (routine checkup with a doctor within last year) data were assessed from age 5 years (1986-2003) until age 17 years (1998-2015). Conducted in 2019, latent class analyses stratified by sex identified well-care use patterns reported over 7 biennial time points adjusted for cohort, race/ethnicity, urbanicity, maternal education, and insurance. RESULTS: A total of 4 well-care use classes emerged for female adolescents: the majority belonged to Engaged (37%) and Moderately Engaged (39%) classes and the remainder belonged to Gradually Re-engaged (14%) and Disengaged-with-Rebound (10%) classes. A total of 3 classes emerged for male adolescents: the majority belonged to the Persistently Disengaged (48%) class and the remainder belonged to Engaged (34%) and Gradually Re-engaged (18%) classes. For both sexes, comparing each cohort with the first, Engaged class membership increased for subsequent cohorts. Less engaged well-care use classes had more non-Hispanic White adolescents living in rural areas with lower insurance coverage. Maternal education differentiated well-care use classes for male but not for female adolescents, being higher for male adolescents in the Engaged class than in other classes. CONCLUSIONS: These findings highlight that well-care use patterns for both sexes changed during the transition from childhood to adolescence and that class membership differed by covariates. These results suggest that sex-specific strategies may be needed to enhance adolescents' well-care use engagement over time.

Genome-wide association study identifies a novel maternal gene × stress interaction associated with spontaneous preterm birth.

BACKGROUND: Maternal stress is potentially a modifiable risk factor for spontaneous preterm birth (sPTB). However, epidemiologic findings on the maternal stress-sPTB relationship have been inconsistent. METHODS: To investigate whether the maternal stress-sPTB associations may be modified by genetic susceptibility, we performed genome-wide gene × stress interaction analyses in 1490 African-American women from the Boston Birth cohort who delivered term (n = 1033) or preterm (n = 457) infants. Genotyping was performed using Illumina HumanOmni 2.5 array. Replication was performed using data from the NICHD genomic and Proteomic Network (GPN) for PTB research. RESULTS: rs35331017, a T-allele insertion/deletion polymorphism in the protein-tyrosine phosphatase receptor Type D (PTPRD) gene, was the top hit that interacted significantly with maternal lifetime stress on risk of sPTB (PG × E = 4.7 × 10-8). We revealed a dose-responsive association between degree of stress and risk of sPTB in mothers carrying the insertion/insertion genotype, but an inverse association was observed in mothers carrying the heterozygous or deletion/deletion genotypes. This interaction was replicated in African-American (PG × E = 0.088) and Caucasian mothers (PG × E = 0.023) from the GPN study. CONCLUSION: We demonstrated a significant maternal PTPRD × stress interaction on sPTB risk. This finding, if further confirmed, may provide new insight into individual susceptibility to stress-induced sPTB. IMPACT: This was the first preterm study to demonstrate a significant genome-wide gene-stress interaction in African Americans, specifically, PTPRD gene variants can interact with maternal perceived stress to affect risk of spontaneous preterm birth. The PTPRD × maternal stress interaction was demonstrated in African Americans and replicated in both African Americans and Caucasians from the GPN study. Our findings highlight the importance of considering genetic susceptibility in assessing the role of maternal stress on spontaneous preterm birth.

China's College Expansion and the Timing of College-to-Work Transition: A Natural Experiment.

This paper examines the causal effect of China's 1999 accelerated expansion of higher education on the timing of finding a first skilled job among college graduates. To test hypotheses derived from applying relevant theories to the China case, we use a natural experiment. The analysis exploits the unique education and work history data of a nationally representative survey and estimates a causal inference model. We find that the 1999 expansion causes a delay in the landing of a skilled job among graduates from technical colleges, while graduates from 4-year colleges are not affected in job acquisition. We also find that family origins and individual social positions remain significant in the selectivity of entering college before and after education expansion acceleration. These findings shed new light on the universal phenomenon of early adulthood and social inequality in China.

Prenatal, Perinatal, and Early Childhood Factors Associated with Childhood Obstructive Sleep Apnea.

OBJECTIVES: To investigate prenatal, perinatal, and early childhood factors, including cord and early childhood plasma leptin, on a clinical diagnosis of obstructive sleep apnea (OSA) among children in the Boston Birth Cohort. STUDY DESIGN: We conducted a secondary analysis of 2867 mother-child pairs from the Boston Birth Cohort who were enrolled between 1998 and 2014 at Boston Medical Center and followed from birth to age 16 years. Child's OSA was defined based on clinical diagnoses documented in the medical record. Plasma leptin was measured in cord and early childhood blood samples. Logistic regression was used to examine individual and combined effects of early life factors on the risk of OSA, adjusting for potential confounders. RESULTS: The mean age of the study children was 6.39 years (SD = 3.77); 49.3% were girls, and 209 (7.3%) had ever been diagnosed with OSA. Four significant risk factors for OSA were identified: maternal obesity/diabetes during pregnancy (OR, 1.63; 95% CI, 1.21-2.21; P = .001), preterm/low birth weight (OR, 1.74; 95% CI, 1.30-2.32; P < .001), early childhood obesity (OR, 1.89; 95% CI, 1.37-2.62; P < .001), and high leptin levels in early childhood (OR, 1.94; 95% CI, 1.22-3.09; P = .005). The presence of all these 4 risk factors significantly amplified the odds of OSA by about 10 times (OR, 9.95; 95% CI, 3.42-28.93; P < .001) compared with those lacking these factors. CONCLUSIONS: Our findings, if further confirmed, provide new insight into the early life risk factors of pediatric OSA and underscore the need for early screening and prevention of OSA among children with those risk factors.

Maternal postpartum plasma folate status and preterm birth in a high-risk US population.

OBJECTIVE: While maternal folate deficiency has been linked to poor pregnancy outcomes such as neural tube defects, anaemia and low birth weight, the relationship between folate and preterm birth (PTB) in the context of the US post-folic acid fortification era is inconclusive. We sought to explore the relationship between maternal folate status and PTB and its subtypes, i.e. spontaneous and medically indicated PTB. DESIGN: Observational study. SETTING: Boston Birth Cohort, a predominantly urban, low-income, race/ethnic minority population at a high risk for PTB.ParticipantsMother-infant dyads (n 7675) enrolled in the Boston Birth Cohort. A sub-sample (n 2313) of these dyads had maternal plasma folate samples collected 24-72 h after delivery. RESULTS: Unadjusted and adjusted logistic regressions revealed an inverse relationship between the frequency of multivitamin supplement intake and PTB. Compared with less frequent use, multivitamin supplement intake 3-5 times/week (adjusted OR (aOR) = 0·78; 95 % CI 0·64, 0·96) or >5 times/week (aOR = 0·77; 95 % CI 0·64, 0·93) throughout pregnancy was associated with reduced risk of PTB. Consistently, higher plasma folate levels (highest v. lowest quartile) were associated with lower risk of PTB (aOR = 0·74; 95 % CI 0·56, 0·97). The above associations were similar among spontaneous and medically indicated PTB. CONCLUSIONS: If confirmed by future studies, our findings raise the possibility that optimizing maternal folate levels across pregnancy may help to reduce the risk of PTB among the most vulnerable US population in the post-folic acid fortification era.

Adolescents' and Young Adults' Routine Care Use: The Role of Their Mothers' Care Use Behaviors.

PURPOSE: Little is known whether mothers' own care use is differentially associated with their adolescents' routine care use by gender. The main purpose of this study is to examine whether mothers' healthcare use prospectively predicts their adolescents' routine care use stratified by gender, after controlling for predisposing (child's age, race/ethnicity, region of residence, urbanicity, and mother's age at child's birth), enabling (mother's education, adolescent and mother health insurance), and need (child health status) factors. METHODS: In 2018, a prospective analysis was conducted using data from 5,040 adolescents aged 9-24 and their mothers who completed the two-generation National Longitudinal Survey of Youth in 2006 (first interview) and 2008 (second interview). Findings include percentages and adjusted odds ratios of the factors that predict adolescents' self-report of routine care use in the past year measured at the second interview. RESULTS: In 2008, over half of participants reported a routine doctor visit during the prior 12 months and this varied by gender; more females (68.7%) had a visit than males (53.5%). Factors that independently predicted a greater odds of adolescents' routine doctor visits included mothers with routine doctor visits at both interviews or the second interview only, and adolescents' health insurance and past routine visit, regardless of gender. Males aged 18-20 and 21-24 years had lower odds of having a routine doctor visit than males aged 9-11 years. CONCLUSIONS: This study provides evidence for the potential role that mothers' care use can play in their adolescents' routine care use, especially for their sons, independent of insurance status.

Agent-Based Modeling of China's Rural-Urban Migration and Social Network Structure.

We analyze China's rural-urban migration and endogenous social network structures using agent-based modeling. The agents from census micro data are located in their rural origin with an empirical-estimated prior propensity to move. The population-scale social network is a hybrid one, combining observed family ties and locations of the origin with a parameter space calibrated from census, survey and aggregate data and sampled using a stepwise Latin Hypercube Sampling method. At monthly intervals, some agents migrate and these migratory acts change the social network by turning within-nonmigrant connections to between-migrant-nonmigrant connections, turning local connections to nonlocal connections, and adding among-migrant connections. In turn, the changing social network structure updates migratory propensities of those well-connected nonmigrants who become more likely to move. These two processes iterate over time. Using a core-periphery method developed from the k-core decomposition method, we identify and quantify the network structural changes and map these changes with the migration acceleration patterns. We conclude that network structural changes are essential for explaining migration acceleration observed in China during the 1995-2000 period.

Uneven Hedging of Economic Risks for a Skilled Workforce: Are Immigrants Disadvantaged?

Skilled immigration to the United States has been multi-channeled via legislations on permanent and temporary visa programs. This paper argues that skilled immigrants were not disadvantaged during the Great Recession because of a new hedging mechanism, which starts with the federal legislations that admit skilled nonimmigrants, proceeds to vest authority in employers, who perform rigorous screening and selection of temporary workers for future permanency, and ends with greater protection of those selected. To test this mechanism, the paper examines skilled immigrants' spatial mobility out of the country and their domestic labor market outcomes. The paper presents evidence from analyzing repeated, nationally representative survey data of college graduates in the US using demographic techniques of intra-cohort and inter-cohort analyses. The major findings about the substantial cross-border mobility and high levels of labor force participation among at-entry temporary visa holders who later gained permanent residency provide strong evidence to support our proposed new hedging mechanism.

The Spatial and Career Mobility of China's Urban and Rural Labor Force.

This paper provides a comprehensive examination of the spatial and career mobility of China's labor population. The paper integrates theories on stratification and social change and exploits the innovative design and measurement of the China Labor-force Dynamics Survey to minimize the under-coverage problem of the rural-urban migratory experience. Our analysis provides several fresh findings: (1) at-birth rural household registration (hukou) status leads to a greater probability of spatial mobility and career advancement than at-birth urban hukou status does; (2) education and gender differentiates rural-origin people, increasing the heterogeneity of urban labor and decreasing the heterogeneity of rural labor; (3) hukou policy relaxation favors later cohorts over earlier cohorts; and (4) among demographically comparable people, having experienced spatial mobility is correlated with having career advancement experience. Work organizations are found to be the arena where the two dimensions of mobility can happen jointly. Our findings provide a rich context for understanding the management and organization of Chinese labor.

Parental Spending on School-Age Children: Structural Stratification and Parental Expectation.

As consumption expenditures are increasingly recognized as direct measures of children's material well-being, they provide new insights into the process of intergenerational transfers from parents to children. Little is known, however, about how parents allocate financial resources to individual children. To fill this gap, we develop a conceptual framework based on stratification theory, human capital theory, and the child-development perspective; exploit unique child-level expenditure data from Child Supplements of the PSID; and employ quantile regression to model the distribution of parental spending on children. Overall, we find strong evidence supporting our hypotheses regarding the effects of socioeconomic status (SES), race, and parental expectation. Our nuanced estimates suggest that (1) parental education, occupation, and family income have differential effects on parental spending, with education being the most influential determinant; (2) net of SES, race continues to be a significant predictor of parental spending on children; and (3) parental expectation plays a crucial role in determining whether parents place a premium on child development in spending and how parents prioritize different categories of spending.

Rural Panel Surveys in Developing Countries: A Selective Review.

Rural panel surveys are the most appropriate means to provide data for studying the unprecedented rapid migration and urbanization currently taking place in China and other developing countries. To maximize heterogeneity in urbanization and development over the last three decades, we selected rural panel surveys from five Asian countries, including India, Indonesia, Nepal, Thailand, and China. This paper provides a selective review, focusing on their panel survey methodology, which is organized based on our proposed four basics of panel surveys - representativeness, retrospect-prospect, multilevel tracking, and temporality. We analyzed the strengths and weaknesses of the selected panel surveys to provide directions for designing future rural panel studies in China and elsewhere in the developing world.

Two Aspects of the Rural-Urban Divide and Educational Stratification in China: A Trajectory Analysis.

Contextualized in China's social change of the past half-century, this paper develops the notion of dichotomous inequality to conceptualize the two aspects of China's rural-urban divide in educational inequality-the household registration system (hukou) assigns people to a top-bottom hierarchy, and the rural-urban schooling system institutionalizes unequal resource distribution and diverse school mission. Based on this conceptualization, we formulate a Chinese version of the maximally maintained inequality (MMI) hypothesis. We capitalize on individual educational history data from the China General Social Survey (CGSS) 2008 and conduct a trajectory analysis using the generalized mixture modeling to estimate the differential effects of the two aspects of rural-urban divide on educational inequality in China. Findings indicate that (1) the sorting mechanism of the rural hukou places rural-hukou people in the very bottom of educational stratification, (2) the penalty of attending rural pre-tertiary school increases with educational stages, and (3) there is a cumulative disadvantage of rural hukou and rural school. Overall, our findings attest to the Chinese-version MMI and the behind principle of inequality reproduction.

Admission-Group Salary Differentials in the United States: The Significance of Labor Market Institutional Selection of High-Skilled Workers.

In 1990 a temporary-to-permanent pathway was established for highly skilled workers admitted to the United States under nonimmigrant programs. The paper argues that this policy shift has allowed employers to play a crucial role in the immigration of highly skilled workers, thereby creating labor-market institutional selection that gives a salary advantage to highly skilled temporary-admitted workers retained in the United States. Through analyses of the salary differentials among admission-category groups, the paper finds that the salary advantage is based on recruitment from Western countries, adjustment from temporary to permanent status after a second employer screening, working in the information technology sector and the private sector, holding a supervisory position, or having a skill-matched job, all of which are consequences of institutional selection rather than individual self-selection. Our results also reveal a difference between those admitted from abroad and those recruited from graduating foreign students in USA higher educational institutions, which suggests a distinction between overseas hiring and domestic hiring. Policy implications for the United States and other receiving countries are discussed.

Distinct trajectories in the transition to adulthood: are children of immigrants advantaged?

Studies on children of immigrants have generally ignored distinct developmental trajectories during adolescence and their role in the transition to adulthood. This study identifies distinct trajectories in cognitive, sociobehavioral, and psychological domains and estimates their consequences for young adults. Drawing data from a nationally representative sample of 10,795 adolescents aged 13-17 who were followed up to ages 25-32, the study uses growth mixture modeling to test advantages for children of immigrants. The analysis shows a 1.5-generation advantage in academic achievement and school engagement, as well as a weaker second-generation advantage in academic achievement, but no disadvantage in depression for children of immigrants. In addition, these results hold for children of Hispanic origin. Theoretical and policy implications are discussed.

Cumulative Causation of Rural Migration and Initial Peri-Urbanization in China.

This paper posits that rural migration feeds the high demand for cheap labor in peri-urbanization, which is driven by globalization, flows of foreign capital, and entrepreneurial local governments. While the gravity model and push/pull perspective ignore the dynamics of migratory course, we use the cumulative causation of migration theory to conceptualize social expectations for outmigration and social resources from migrant networks in destinations. Four major findings are drawn from this demographic analysis based on micro data from China's 2000 Census. First, the expectation of outmigration significantly increases outmigration, and this effect is independent of push factors. Second, foreign direct investment (FDI) contributes to attracting rural labor migrants from other provinces to peri-urban areas as it does to cities. Third, social resources from migrant networks play an important role in attracting rural labor migrants to both city and noncity destinations. Fourth, the importance of wage differentials declines in gravitating rural labor migrants to peri-urban areas. These findings provide tentative evidence that rural labor migration is indispensable during initial peri-urbanization. Infused with flows of FDI and entrepreneurial local governments, rural migration has created a favorable initial condition for peri-urbanization.

Linking Dichotomous Segregation with Multi-group Segregation: Weighted Segregation Ratios in Selected U. S. Metropolitan Areas.

The U. S. residential landscape is increasingly multi-racial and multi-ethnic, giving rise to the question of how to compare dichotomous segregation among multiple groups living in the same area. To address the problem in the existing dichotomous approach, which offers no common basis for comparing dichotomous segregation among multiple groups, this paper develops a weighted segregation ratio approach based on Theil's segregation index and its additive decomposability. This approach can be used to bridge information obtained from dichotomous segregation between specific groups (such as black-white and black-Hispanic), and dichotomous segregation between group and non-group (such as white-non-white and black-non-black) in previous studies. We apply both dichotomous and weighted segregation ratio approaches to 1990 and 2000 U. S. census data. Results are interpreted for five selected metropolitan areas as well as for the weighted national average. This new approach yields distinctive findings that portray the complicated process of residential segregation, including the increasing significance of Hispanic segregation and Asian segregation in the decade from 1990 to 2000.