Cohort profile: the mature adults cohort of the Malawi longitudinal study of families and health (MLSFH-MAC)

Prevalence and early-life predictors of adverse childhood experiences: Longitudinal insights from a low-income country

BACKGROUND

A sizeable literature shows that adverse childhood experiences (ACEs) are associated with poor health outcomes in later life. However, most studies on the prevalence and predictors of ACEs have been carried out in high-income countries using cross-sectional approaches.

OBJECTIVE

The present study explores the prevalence and predictors of ACEs in Malawi, a low-income country, using prospective longitudinal data collected on adolescents.

PARTICIPANTS

We use data on 1375 adolescents and their biological mothers from the Malawi Longitudinal Study of Families and Health (MLSFH). ACEs were reported by adolescents over two survey waves, in 2017-18 and 2021. Predictors were reported by mothers in 2008 and 2010.

METHODS

Multivariate ordinary least square and logistic regression analyses of ACEs exposure reported by adolescents on indicators of family arrangements and resources.

RESULTS

Adolescents report having been exposed to nearly seven ACEs on average. Among indicators of family arrangements and resources, the only significant predictors of cumulative ACEs exposure are polygyny (linked to parental absence) and mother's SF-12 mental health score (linked to physical abuse and witnessing domestic violence).

CONCLUSIONS

ACEs are much more prevalent in the low-income country under study than in middle- and high-income countries surveyed in prior research. Despite adversity being widespread, most indicators of family arrangements and resources highlighted in prior studies are not associated with adolescents' cumulative ACEs exposure in this context. Mothers' mental health in childhood nevertheless emerges as a significant predictor of adolescents' self-reported ACEs. These findings inform efforts aimed at preventing ACEs in high-adversity contexts.

Mortality risk information and health-seeking behavior during an epidemic

In a context where pessimistic survival perceptions have been widespread as a result of the HIV/AIDS epidemic (Fig. 1 A), we study vaccine uptake and other health behaviors during the recent COVID-19 pandemic. Leveraging a longitudinal cohort study in rural Malawi that has been followed for up to 25 y, we document that a 2017 mortality risk information intervention designed to reduce pessimistic mortality perceptions (Fig. 1 B) resulted in improved health behavior, including COVID-19 vaccine uptake (Fig. 1 C). We also report indirect effects for siblings and household members. This was likely the result of a reinforcing process where the intervention triggered engagement with the healthcare system and stronger beliefs in the efficacy of modern biomedical treatments, which led to the adoption of health risk reduction behavior, including vaccine uptake. Our findings suggest that health information interventions focused on survival perceptions can be useful in promoting health behavior and participation in the formal healthcare system, even during health crises-such as the COVID-19 pandemic-that are unanticipated at the time of the intervention. We also note the importance of the intervention design, where establishing rapport, tailoring the content to the local context, and spending time with respondents to convey the information contributed to the salience of the message.

Cohort profile: the Adverse Childhood Experiences cohort of the Malawi Longitudinal Study of Families and Health

PURPOSE

The Adverse Childhood Experiences (ACE) cohort of the Malawi Longitudinal Study of Families and Health (MLSFH-ACE) is a study of adolescents surveyed during 2017-2021. It provides an important opportunity to examine the longitudinal impact of ACEs on health and development across the early life course. The MLSFH-ACE cohort provides rich data on adolescents, their children and adult caregivers in a low-income, high-HIV-prevalence context in sub-Saharan Africa (SSA).

PARTICIPANTS

The MLSFH-ACE cohort is a population-based study of adolescents living in three districts in rural Malawi. Wave 1 enrolment took place in 2017-2018 and included 2061 adolescents aged 10-16 years and 1438 caregivers. Wave 2 took place in 2021 and included data on 1878 adolescents and 208 offspring. Survey instruments captured ACEs during childhood and adolescence, HIV-related behavioural risk, mental and physical health, cognitive development and education, intimate partner violence (IPV), marriage and aspirations, early transitions to adulthood and protective factors. Biological indicators included HIV, herpes simplex virus and anthropometric measurements.

FINDINGS TO DATE

Key findings include a high prevalence of ACEs among adolescents in Malawi, a low incidence of HIV and positive associations between ACE scores and composite HIV risk scores. There were also strong associations between ACEs and both IPV victimisation and perpetration.

FUTURE PLANS

MLSFH-ACE data will be publicly released and will provide a wealth of information on ACEs and adolescent outcomes in low-income, HIV-endemic SSA contexts. Future expansions of the cohort are planned to capture data during early adulthood.

MORTALITY RISK INFORMATION, SURVIVAL EXPECTATIONS AND SEXUAL BEHAVIOURS

We investigate the impact of a randomised information intervention about population-level mortality on health investment and subjective health expectations. Our focus is on risky sex in a high-HIV-prevalence environment. Treated individuals are less likely to engage in risky sexual practices one year after the intervention, with, for example, an 8% increase in abstinence. We collected detailed data on individuals' subjective expectations about their own and population survival, as well as other important health outcomes. Our findings emphasise the significance of integrating subjective expectation data in field experiments to identify the pathways that lead to behavioural change.

Barker's Hypothesis Among the Global Poor: Positive Long-Term Cardiovascular Effects of in Utero Famine Exposure

An influential literature on the Developmental Origins of Health and Disease (DOHaD) has documented that poor conditions in utero lead to higher risk of cardiovascular disease at older ages. Evidence from low-income countries (LICs) has hitherto been missing, despite the fact that adverse in utero conditions are far more common in LICs. We find that Malawians exposed in utero to the 1949 Nyasaland famine have better cardiovascular health 70 years later. These findings highlight the potential context specificity of the DOHaD hypothesis, with in utero adversity having different health implications among aging LIC individuals who were exposed to persistent poverty.

Cognition and Cognitive Changes in a Low-Income Sub-Saharan African Aging Population

BACKGROUND

Cognition and its age-related changes remain vastly understudied in low-income countries (LICs), despite evidence suggesting that cognitive decline among aging low-income populations is a rapidly increasing disease burden often occurring at younger ages as compared to high-income countries (HICs).

OBJECTIVE

We examine patterns of cognition among men and women, 45 + years old, living in rural Malawi. We analyze how key socioeconomic characteristics predict levels of cognition and its changes as individuals get older.

METHODS

Utilizing the Mature Adults Cohort of the Malawi Longitudinal Study of Families and Health (MLSFH-MAC) collected during 2012-2017, we estimate standard regression models to analyze predictors of the age- and sex-specific levels and longitudinal changes in cognition. Cognition is assessed with a screening instrument that is adapted to this low-literacy context and measures different domains such as language, attention, or executive functioning.

RESULTS

Women have lower levels of cognition than men, a pattern in stark contrast to findings in HICs. Schooling and socioeconomic status increase the probability of having consistently high performance during the cognitive assessment. Cognitive decline accelerates with age and is detectable already at mid-adult ages (45-55 years). Despite lower levels of cognitive function observed among women, the pace of decline with age is similar for both genders.

CONCLUSION

Women are particularly affected by poor cognition in this context. The study emphasizes the importance of prioritizing cognitive health and research on cognition among older individuals in sub-Saharan Africa LICs, to which relatively little health care resources continue to be allocated.

Mental health and life-course shocks in a low-income country: Evidence from Malawi

Economic insecurity has been widely hypothesized to be an important determinant of mental health, but this relationship has not been well-documented in low-income countries. Using data from the Mature Adults Cohort of the Malawi Longitudinal Study of Families and Health (MLSFH-MAC), we investigate the association of negative economic shocks with mental health outcomes such as depression and anxiety among adults aged 45+ years living in a low-income country. Using fixed effects estimates that control for time-invariant unobserved individual heterogeneity, we find that increased economic instability caused by events such as death of a family member, yield loss, or income loss is positively associated with worse mental health outcomes as measured by the PHQ-9 and GAD-7 instruments. Our results suggest that costly economic events are a key component to worsening mental health in settings characterized by pervasive poverty and underscore the importance of mental health as a public health and development target.

Path Dependence in Disability

The average prevalence of disability in most African countries is 10%, but for many it exceeds the global disability prevalence rate of 15%. The extent to which this disability capturing functional and activity limitations results in permanent job loss, lowered lifetime income and assets, in part, depends upon the extent to which the onset of limitations becomes permanent. In this paper, we use five rounds of longitudinal data from rural Malawi, a low-income African country with high prevalence of disability, to examine path dependence in activity limitations. We estimate a dynamic linear panel data model where the coefficient on the one-period lagged health outcome captures path dependence in limitations. Our preferred Arellano-Bover estimates show that males experience partial persistence in both the incidence and intensity of severe limitations and no persistence in other limitations. Females, on the other hand, exhibit no persistence in any type of limitations. Our findings have important policy implications for computing the long-term costs associated with onset of activity limitations as these costs can be moderated by the recovery exhibited in these limitations.

Aging and hypertension among the global poor-Panel data evidence from Malawi

Hypertension is a rapidly growing disease burden among older persons in low-income countries (LICs) that is often inadequately diagnosed and treated. Yet, most LIC research on hypertension is based on cross-sectional data that does not allow inferences about the onset or persistence of hypertension, its correlates, and changes in hypertension as individuals become older. The Mature Adults Cohort of the Malawi Longitudinal Study of Families and Health (MLSFH-MAC) is used to provide among the first panel analyses of hypertension for older individuals in a sub-Saharan LIC using blood pressure measurements obtained in 2013 and 2017. We find that high blood pressure is very common among mature adults aged 45+, and hypertension is more prevalent among older as compared to middle-aged respondents. Yet, in panel analyses for 2013-17, we find no increase in the prevalence of hypertension as individuals become older. Hypertension often persists over time, and the onset of hypertension is predicted by factors such as being overweight/obese, or being in poor physical health. Otherwise, however, hypertension has few socioeconomic predictors. There is also no gender differences in the level, onset or persistence in hypertension. While hypertension is associated with several negative health or socioeconomic consequences in longitudinal analyses, cascade-of-care analyses document significant gaps in the diagnosis and treatment of hypertension. Overall, our findings indicate that hypertension and related high cardiovascular risks are widespread, persistent, and often not diagnosed or treated in this rural sub-Saharan population of older individuals. Prevalence, onset and persistence of hypertension are common across all subgroups-including, importantly, both women and men. While age is an important predictor of hypertension risk, even in middle ages 45-55 years, hypertension is already widespread. Hypertension among adults aged 45+ in Malawi is thus more similar to a "generalized epidemic" than in high-income countries where cardiovascular risk has strong socioeconomic gradients.

Pain Is Widespread and Predicts Poor Mental Health Among Older Adults in Rural Malawi

Background and Objectives

Pain is common among older persons and has been documented as an important predictor of disability, health, and economic outcomes. Evidence about its prevalence and relationship to well-being is scarce in rural sub-Saharan Africa (SSA), where work is frequently physically demanding, and pain prevention or treatment options are limited. We investigate the prevalence of pain and its association with mental health and subjective well-being in a population-based study of older adults in rural Malawi.

Research Design and Methods

We estimate the prevalence, severity, and duration of pain along with its sociodemographic distribution in a sample of 1,577 individuals aged 45 and older. We assess the association of pain with clinically validated measures of mental health, including depression and anxiety, and subjective well-being.

Results

Pain is widespread in this mature population with an average age of 60 years: 62% of respondents report the experience of at least minor pain during the last year, and half of these cases report severe or disabling pain. Women are more likely to report pain than men. Pain is a strong predictor of mental health and subjective well-being for both genders. More severe or longer pain episodes are associated with worse mental states. Individuals reporting pain are more likely to suffer from depression or express suicidal thoughts.

Discussion and Implications

Our study identifies key subpopulations such as older women in a SSA low-income context who are particularly affected by the experience of pain in daily life and calls for interventions targeting pain and its consequences for mental health and subjective well-being.

Curtailing Covid-19 on a dollar-a-day in Malawi: Role of community leadership for shaping public health and economic responses to the pandemic

Utilizing population-based data from the Covid-19 phone survey ( N = 2 , 262 ) of the Malawi Longitudinal Study of Families and Health (MLSFH) collected during June 2nd-August 17th, 2020, we focus on the crucial role that community leadership and trust in institutions played in shaping behavioral, economic and social responses to Covid-19 in this low-income sub-Saharan African context. We argue that the effective response of Malawi to limit the spread of the virus was facilitated by the engagement of local leadership to mobilize communities to adapt and adhere to Covid-19 prevention strategies. Using linear and ordered probit models and controlling for time fixed effects, we show that village heads (VHs) played pivotal role in shaping individuals' knowledge about the pandemic and the adoption of preventive health behaviors and were crucial for mitigating the negative economic and health consequences of the pandemic. We further show that trust in institutions is of particular importance in shaping individuals' behavior during the pandemic, and these findings highlight the pivotal role of community leadership in fostering better compliance and adoption of public health measures essential to contain the virus. Overall, our findings point to distinctive patterns of pandemic response in a low-income sub-Saharan African rural population that emphasized local leadership as mediators of public health messages and policies. These lessons from the first pandemic wave remain relevant as in many low-income countries behavioral responses to Covid-19 will remain the primary prevention strategy for a foreseeable future.

Cohort and Period Effects as Explanations for Declining Dementia Trends and Cognitive Aging

Studies have reported that the age-adjusted incidence of cognitive impairment and dementia may have decreased over the past two decades. Aging is the predominant risk factor for Alzheimer's disease and related dementias and for neurocognitive decline. However, aging cannot explain changes in overall age-adjusted incidence of dementia. The objective of this position paper was to describe the potential for cohort and period effects in cognitive decline and incidence of dementia. Cohort effects have long been reported in demographic literature, but starting in the early 1980s, researchers began reporting cohort trends in cognitive function. At the same time, period effects have emerged in economic factors and stressors in early and midlife that may result in reduced cognitive dysfunction. Recognizing that aging individuals today were once children and adolescents, and that research has clearly noted that childhood cognitive performance is a primary determinant of old-age cognitive performance, this is the first study that proposes the need to connect known cohort effects in childhood cognition with differences in late-life functioning.

Marital dissolutions and changes in mental health: Evidence from rural Malawi

BACKGROUND

Advancing efforts to unpack the complex relationship between marital dissolutions and health outcomes increasingly requires assessing the marital histories and health of individuals who have lived long enough to experience divorce or widowhood ‒ or even multiples of each ‒ and measurable changes in health.

OBJECTIVE

To explore this line of inquiry, we chose a sample from rural Malawi where a high prevalence of marital dissolutions and remarrying exists, as an ideal theoretical foil to the predominant literature found in high-income countries (HICs). We examine if changes in having experienced a marital dissolution, one's total number of dissolutions, and the percentage of one's life spent outside of marriage since first becoming married are associated with changes in mental health.

METHODS

Our analyses focus on 1,266 respondents aged 45 years and older who participated in the 2012 Mature Adults Cohort of the Malawi Longitudinal Study of Families and Health (MLSFH-MAC), linked back to cohort information from 2008 and 2010 available through the MLSFH. Fixed-effects regressions guide our inferences over the 2008, 2010, and 2012 waves of data.

RESULTS

For men, spending more life outside of marriage is associated with worse mental health, while more marital dissolutions are surprisingly associated with better mental health for women.

CONCLUSIONS

These results could suggest that larger portions of one's life spent unmarried are associated with a type of role strain for men or simply that men are burdened with taking up tasks that their spouses had previously done in order to survive. For women, many may have gotten out of 'bad' marriages that otherwise would have been detrimental to their mental health and/or those in good mental health are the ones able to remarry.

CONTRIBUTIONS

Our research from rural Malawi provides a type of litmus test for many HICs where marriage, remarriage, and dissolution rates are lower but quite consequential for mental health outcomes. Measuring time outside of marriage should be more strongly considered in such settings. These results also inform increasingly important research on the relationship between marital dissolutions and mental health in other African nations as noncommunicable diseases play a continually more important role in people's lives.

Health screening for emerging non-communicable disease burdens among the global poor: Evidence from sub-Saharan Africa

Evidence for the effectiveness of population health screenings to reduce the burden of non-communicable diseases in low-income countries remains very limited. We investigate the sustained effects of a health screening in Malawi where individuals received a referral letter if they had elevated blood pressure. Using a regression discontinuity design and a matching estimator, we find that receiving a referral letter reduced blood pressure and the probability of being hypertensive by about 22 percentage points four years later. These lasting effects are explained by a 20 percentage points increase in the probability of being diagnosed with hypertension. There is also evidence of an increase in the uptake of medication, while we do not identify improvements in hypertension-related knowledge or risk behaviors. On the contrary, we find an increase in sugar intake and a decrease in physical activity both of which are considered risky behaviors in Western contexts. The health screening had some positive effects on mental health. Overall, this study suggests that population-based hypertension screening interventions are an effective tool to improve health in low-income contexts.