Seroprevalence of IgG antibodies against diphtheria antitoxin among migrant workers in Singapore, 2016–2019

Background Since the last local case of diphtheria in 1992, there had not been any case in Singapore until an autochthonous case was reported in 2017. This fatal diphtheria case of a migrant worker raised concerns about the potential re-emergence of locally transmitted toxigenic diphtheria in Singapore. We conducted a seroprevalence study to assess the immunity levels to diphtheria among migrant workers in Singapore. Methods Residual sera from migrant workers who hailed from Bangladesh, China, India, Indonesia, Malaysia, Myanmar and the Philippines were tested for anti-diphtheria toxoid immunoglobulin G (IgG) antibodies. These migrant workers previously participated in a survey between 2016 and 2019 and had provided blood samples as part of the survey procedure. Results A total of 2176 migrant workers were included in the study. Their overall mean age was 27.1 years (standard deviation 5.0), range was 20–43 years. The proportion having at least basic protection against diphtheria (antitoxin titres ≥ 0.01 IU/ml) ranged from 77.9% (95% confidence interval [CI] 72.8 – 82.3%) among migrant workers from Bangladesh to 96.7% (95% CI 92.5 – 98.6%) in those hailing from Malaysia. The proportion showing full protection (antitoxin titres ≥ 0.10 IU/ml) ranged from 10.1% (95% CI 6.5 – 15.4%) in Chinese workers to 23.0% (95% CI 17.1 – 30.3%) in Malaysian workers. There were no significant differences in the proportion with at least basic protection across birth cohorts, except for those from Bangladesh where the seroprevalence was significantly lower in younger migrant workers born after 1989. Conclusions The proportions having at least basic protection against diphtheria in migrant workers from five out of seven Asian countries (India, Indonesia, Malaysia, Myanmar and the Philippines) were higher than 85%, the threshold for diphtheria herd immunity. Seroprevalence surveys should be conducted periodically to assess the level of immunity against diphtheria and other vaccine preventable diseases in migrant worker population, so that appropriate interventions such as booster vaccination can be implemented proactively to prevent sporadic outbreaks.

Socioeconomic and sex inequalities in parent-reported adolescent mental ill-health: Time trends in four British birth cohorts

BackgroundStudies using symptom-based screeners have suggested that mental health problems have increased in adolescents in recent decades, however, few studies have explicitly tested the equivalence of their instruments, which is critical for inferring changes in prevalence. In addition, few studies have explored whether changes in socioeconomic position (SEP) and sex inequalities across generations have impacted trends in adolescent mental health. MethodsUsing structural equation modelling, we explore sex differences in harmonised parent-reports of emotional and behavioural problems, using data from four UK birth cohorts: the 1958 National Child Development Study (NCDS’58; N= 11,398), the 1970 British Cohort Study (BCS’70; N= 8,161), the 1991-92 Avon Longitudinal Study of Parents and Children (ALSPAC’91; N= 5,304), and the 2001 Millennium Cohort Study (MCS’01; N= 10,384). We also delineate associations between four harmonised indicators of childhood SEP and adolescent mental health, and test whether changes in SEP account for increases in mental ill-health over time. Results We found an increase in the latent means of parent-reported emotional and behavioural problems across time in both males and females in more recent cohorts, with the exception of ALSPAC’91. Sex-inequalities did not change over time, with females having consistently higher emotional problems. The associations between the four indicators of SEP and emotional problems were strongest in the MCS’01, with housing tenure having the strongest association. All four SEP indicators were associated with behavioural problems in all of the cohorts, with housing tenure again more strongly associated with problems in the MCS’01. Inconsistent mediation (i.e. regression suppression) suggested that the increases in mental health problems occurred despite broadly improving average socio-economic conditions. ConclusionsOur findings suggest that parent-reported adolescent mental health problems have risen in recent generations and that this trend is not due solely to reporting styles. A failure to address widening inequalities may result in further increases in mental ill-health amongst disadvantaged young people.

Less is more or more is more? Union dissolution and re-partnering as an engine for fertility in a demographic forerunner context – a register based completed cohort fertility approach

Extensive literature theorizes the role of re-partnering on cohort fertility and whether union dissolution can be an engine for fertility. A large share of higher-order unions is non-marital cohabitations. Yet, most previous completed cohort fertility studies on the topic analyze marital unions only and none have measured cohabitations using population-level data. We use Finnish register data to enumerate every birth, marriage, and cohabitation from ages 18-46 in the 1969–1972 birth cohorts, and analyze the relationship between the number of unions and cohort fertility for men and women using Poisson regression. We show that re-partnering is driven by cohabitations. Re-marriage is positively associated with cohort fertility, compared to individuals in a single intact marriage. However, when measured using marriages as well as non-marital cohabitations, re-partnering is negatively associated with fertility, compared to individuals in a single intact union. This negative association increases with socioeconomic status. “Serial cohabitation” is a strong predictor of low fertility. Men see a slight “re-marriage premium” in fertility and a (non-marital) “re-partnering penalty,” compared to women. Thus, re-partnering is likely not an efficient engine for fertility. Further, marriage and cohabitation are far from indistinguishable in a country often described as a second demographic transition forerunner.

Childhood hearing impairment and fertility in Norway

There is a lack of studies assessing how hearing impairment relates to reproductive outcomes. We examined whether childhood hearing impairment (HI) affects reproductive patterns based on longitudinal Norwegian population level data for birth cohorts 1940–1980. We used Poisson regression to estimate the association between the number of children ever born and HI. The association with childlessness is estimated by a logit model. As a robustness check, we also estimated family fixed effects Poisson and logit models. Hearing was assessed at ages 7, 10 and 13, and reproduction was observed at adult ages until 2014. Air conduction hearing threshold levels were obtained by pure-tone audiometry at eight frequencies from 0.25 to 8 kHz. Fertility data were collected from Norwegian administrative registers. The combined dataset size was N = 50,022. Our analyses reveal that HI in childhood is associated with lower fertility in adulthood, especially for men. The proportion of childless individuals among those with childhood HI was almost twice as large as that of individuals with normal childhood hearing (20.8% vs. 10.7%). The negative association is robust to the inclusion of family fixed effects in the model that allow to control for the unobserved heterogeneity that are shared between siblings, including factors related to the upbringing and parent characteristics. Less family support in later life could add to the health challenges faced by those with HI. More attention should be given to how fertility relates to HI.

Sample management: a primary critical starting point for successful omics studies

Biological samples collected from cohort studies are widely utilized in molecular genetic studies and are typically stored long term for future applications, such as omics analyses. The extent of sample availability is determined by proper sample handling, and it is of primary importance for successful omics studies. However, questions on whether samples in long-term storage are properly available for omics experiments has been raised, because the quality and availability of such samples remain unknown until their actual utilization. In that perspective, several guidelines for proper sample management have been suggested. In addition, several researchers assessed how improper management damages sample using mock sample and suggested a set of requirements for sample handling. In this review, we present several considerations for sample handling eligible for omics studies. Focusing on birth cohorts, we describe the types of samples collected from which omics data were generated. This review ultimately aims to provide proper guidelines for sample handling for successful human omics studies.

Structural Change Shapes Career Mobility Opportunities: An Analysis of Cohorts, Gender and Parental Class

Research suggests that structural change drives occupational mobility in high-income countries over time, but two partially competing theories explain how such change occurs. One suggests that younger cohorts replace older ones through higher education, and the second suggests that individuals adapt to structural change by switching from declining to new or growing occupations during their careers. A proposed occupational scheme aligns with the two dimensions of structural change – skill upgrading on the vertical axis of occupational differentiation, increasing demand for data comprehension (i.e. high skill) and primary tasks concerning either people or things on the horizontal axis. Applied to career trajectories in the Swedish labour market, sequence analyses of the scheme suggest stability in attainment of career mobility types over time between consecutive birth cohorts, and considerable evidence for within-career manoeuvring. Analyses address heterogeneity along parental class and gender.

Trends and country-level variation in age at first sex in sub-Saharan Africa among birth cohorts entering adulthood between 1985 and 2020

Background: Debuting sexual intercourse is a life course event marking exposure to pregnancy or fatherhood, and sexually transmitted infections (STIs), including HIV. We systematically analysed the timing, distribution, and trends in age at first sex (AFS) in 42 sub-Saharan Africa (SSA) countries. Methods: We collated individual-level AFS data from nationally representative household surveys across SSA. We used a log-skew-logistic distribution to model the distribution of AFS in a Bayesian spatio-temporal hierarchical random-effect model to estimate national trends of AFS over time and space, adjusting for age at report biases. Findings: Small changes in AFS are observed between the birth cohorts entering adulthood between 1985 and 2020, ranging 0.79 years [-0.01-1.51] and 0.48 [-0.03-1.92] for female and male, respectively. Northern SSA countries show appreciable increase in AFS but its gender gap remains the widest compared with minimal gender gap in the southern countries. The gender gap shows little evidence of change over time in most of the countries. Female's AFS approach to a similar age across SSA while male's AFS varies between regions. Proportion ever had sex under fifteen and eighteen are as high 34% and 83%, respectively. AFS distribution is typically asymmetric with most of sexual debut events occur in a span of 3.9 [3.4-5.0] years. Female teen often reports higher AFS compare to their late twenties while male teen report lower AFS; both sexes tend to recall a higher AFS in older ages compared to their thirties. Interpretation: Women debut sexually earlier and in a shorter span of age than men. Northern and southern SSA gender gap are distinctively different. Since the ratifying of HIV/AIDS intervention programs in SSA, a stagnant trend in AFS had remained in the countries most affected by the epidemic.

Birth cohort differences in height, weight and body mass index among Indian women aged 15-30 years: Analyses based on three cross-sectional surveys

Objective: To explore long-term trends in height, weight and body mass index (BMI) across birth cohorts among Indian women aged 15-30. Design: Nationally representative cross-sectional surveys. Setting: Data from three National Family Health Surveys conducted in 1998-99, 2005-06 and 2015-16. Height and weight were modeled jointly, employing a multivariate regression model with age and birth cohorts as explanatory variables. The largest birth cohort (born 1988-92) was the reference cohort. Stratified analyses by place of residence and by marital status and dichotomized parity were also performed. Participants: 437,753 non-pregnant women aged 15-30 years. Results: The rate of increase in height, weight and BMI differed across birth cohorts. The rate of increase was much lower for height than weight, which was reflected in an increasing trend in BMI across all birth cohorts. In the stratified analyses, increase in height was found to be similar across urban and rural areas. Rural women born in the latest birth cohort (1998-2001) were lighter, whereas urban women were heavier compared to the reference cohort. A relatively larger increase in regression coefficients were observed among women born between 1978-82 compared to women born between 1973-77 when considering unmarried and nulliparous ever-married women and, one cohort later (1983-87 vs. 1978-82), among parous ever-married women. Conclusion: As the rate of increase was much larger for weight than for height, increasing trends in BMI were observed across the birth cohorts. Thus, cohort effects show an important contributory role in explaining increasing trends in BMI among young Indian women.