More (Adjustment) Is Not Always Better: How Directed Acyclic Graphs Can Help Researchers Decide Which Covariates to Include in Models for the Causal Relationship between an Exposure and an Outcome in Observational Research

Pooled lagged effect of runoff on leptospirosis cases in Colombia

Leptospirosis is a global zoonotic disease caused by spirochete bacteria of the genus Leptospira. The disease exhibits a notable incidence in tropical and developing countries, and in Colombia, environmental, economic, social, and cultural conditions favor disease transmission, directly impacting both mortality and morbidity rates. Our objective was to establish the pooled lagged effect of runoff on leptospirosis cases in Colombia. For our study, we included the top 20 Colombian municipalities with the highest number of leptospirosis cases. Monthly cases of leptospirosis, confirmed by laboratory tests and spanning from 2007 to 2022, were obtained from the National Public Health Surveillance System. Additionally, we collected monthly runoff and atmospheric and oceanic data from remote sensors. Multidimensional poverty index values for each municipality were sourced from the Terridata repository. We employed causal inference and distributed lag nonlinear models to estimate the lagged effect of runoff on leptospirosis cases. Municipality-specific estimates were combined through meta-analysis to derive a single estimate for all municipalities under study. The pooled results for the 20 municipalities suggest a lagged effect for the 0 to 2, and 0-3 months of runoff on leptospirosis when the runoff is < 120 g/m2. No effect was identified for longer lagged periods (0-1, 0 to 4, 0 to 5, and 0-6 months) or higher runoff values. Incorporation of the multidimensional poverty index into the meta-analysis of runoff contributed to the models for the lagged periods of 0-3, and 0-4 months.

Causal association between environmental variables and the excess cases of cutaneous leishmaniasis in Colombia: are we looking to the wrong side?

Our main aim was to estimate and compare the effects of six environmental variables (air temperature, soil temperature, rainfall, runoff, soil moisture, and the enhanced vegetation index) on excess cases of cutaneous leishmaniasis in Colombia. We used epidemiological data from the Colombian Public Health Surveillance System (January 2007 to December 2019). Environmental data were obtained from remote sensing sources including the National Oceanic and Atmospheric Administration, the Global Land Data Assimilation System (GLDAS), and the Moderate Resolution Imaging Spectroradiometer. Data on population were obtained from the TerriData dataset. We implemented a causal inference approach using a machine learning algorithm to estimate the causal association of the environmental variables on the monthly occurrence of excess cases of cutaneous leishmaniasis. The results showed that the largest causal association corresponded to soil moisture with a lag of 3 months, with an average increase of 8.0% (95% confidence interval [CI] 7.7-8.3%) in the occurrence of excess cases. The temperature-related variables (air temperature and soil temperature) had a positive causal effect on the excess cases of cutaneous leishmaniasis. It is noteworthy that rainfall did not have a statistically significant causal effect. This information could potentially help to monitor and control cutaneous leishmaniasis in Colombia, providing estimates of causal effects using remote sensor variables.

The natural course of binge-eating disorder: findings from a prospective, community-based study of adults

BACKGROUND

Epidemiological data offer conflicting views of the natural course of binge-eating disorder (BED), with large retrospective studies suggesting a protracted course and small prospective studies suggesting a briefer duration. We thus examined changes in BED diagnostic status in a prospective, community-based study that was larger and more representative with respect to sex, age of onset, and body mass index (BMI) than prior multi-year prospective studies.

METHODS

Probands and relatives with current DSM-IV BED (n = 156) from a family study of BED ('baseline') were selected for follow-up at 2.5 and 5 years. Probands were required to have BMI > 25 (women) or >27 (men). Diagnostic interviews and questionnaires were administered at all timepoints.

RESULTS

Of participants with follow-up data (n = 137), 78.1% were female, and 11.7% and 88.3% reported identifying as Black and White, respectively. At baseline, their mean age was 47.2 years, and mean BMI was 36.1. At 2.5 (and 5) years, 61.3% (45.7%), 23.4% (32.6%), and 15.3% (21.7%) of assessed participants exhibited full, sub-threshold, and no BED, respectively. No participants displayed anorexia or bulimia nervosa at follow-up timepoints. Median time to remission (i.e. no BED) exceeded 60 months, and median time to relapse (i.e. sub-threshold or full BED) after remission was 30 months. Two classes of machine learning methods did not consistently outperform random guessing at predicting time to remission from baseline demographic and clinical variables.

CONCLUSIONS

Among community-based adults with higher BMI, BED improves with time, but full remission often takes many years, and relapse is common.

Association between Dietary Patterns during Pregnancy and Children's Neurodevelopment: A Birth Cohort Study

BACKGROUND

Research studies have showed that maternal diet may influence fetal neurodevelopment, but most studies have only assessed single nutrients or food groups.

OBJECTIVE

To investigate the impact of maternal prenatal dietary patterns during pregnancy on child neurodevelopment.

METHODS

Study participants were obtained from the China National Birth Cohort. The Ages and Stages Questionnaire, Third Edition, was used to assess children's neurodevelopment at 36 months old. Maternal antenatal dietary data were collected over three trimesters using food frequency questionnaires. Five distinct maternal dietary patterns throughout pregnancy were identified by principal component analysis, namely protein- and micronutrient-rich dietary patterns, low-iron dietary patterns, pasta as the staple food dietary patterns, iron-rich dietary patterns, tubers, fruits, and baked food dietary patterns. Group-based trajectory modeling was performed for dietary patterns present in all three periods. Multiple linear regression models were used for statistical analysis.

RESULTS

Children of mothers who followed a high protein- and micronutrient-rich dietary pattern trajectory during pregnancy presented better neurodevelopment, including higher gross motor and problem-solving scores. Furthermore, it was observed that children born of women with low-iron dietary patterns had poorer neurodevelopment. In detail, children born to mothers with a low-iron dietary pattern during the first trimester had lower problem-solving scores, while to those who were exposed to a low-iron dietary pattern in the second and third trimesters had lower gross motor scores. Additionally, children with mothers who had a low-iron dietary pattern in the third trimester had lower communication scores.

CONCLUSIONS

A nutrition-balanced protein- and micronutrient-rich dietary pattern and adequate iron dietary pattern for mothers throughout pregnancy may be beneficial to children's neurodevelopment.

Could the association between ozone and arterial stiffness be modified by fish oil supplementation?

BACKGROUND

Arterial stiffness (AS) is an important predicting factor for cardiovascular disease. However, no epidemiological studies have ever explored the mediating role of biomarkers in the association between ozone and AS, nor weather fish oil modified such association.

METHODS

Study participants were drawn from the UK biobank, and a total of 95,699 middle-aged and older adults were included in this study. Ozone was obtained from Community Multiscale Air Quality (CMAQ) model matched to residential addresses, fish oil from self-reported intake, and arterial stiffness was based on device measurements. First, we applied a double robust approach to explore the association between ozone or fish oil intake and arterial stiffness, adjusting for potential confounders at the individual and regional levels. Then, how triglycerides, apolipoprotein B (Apo B)/apolipoprotein A (ApoA) and non-high-density lipoprotein cholesterol (Non-HDL-C) mediate the relationship between ozone and AS. Last, the modifying role of fish oil was further explored by stratified analysis.

RESULTS

The mean age of participants was 55 years; annual average ozone exposure was associated with ASI (beta:0.189 [95%CI: 0.146 to 0.233], P < 0.001), and compared to participants who did not consume fish oil, fish oil users had a lower ASI (beta: 0.061 [95%CI: -0.111 to -0.010], P = 0.016). The relationship between ozone exposure and AS was mediated by triglycerides, ApoB/ApoA, and Non-HDL-C with mediation proportions ranging from 10.90% to 18.30%. Stratified analysis showed lower estimates on the ozone-AS relationship in fish oil users (P = 0.011).

CONCLUSION

Ozone exposure was associated with higher levels of arterial stiffness, in contrast to fish oil consumption, which showed a protective association. The association between ozone exposure and arterial stiffness was partially mediated by some biomarkers. In the general population, fish oil consumption might provide protection against ozone-related AS.

Early-life exposure to tobacco, genetic susceptibility, and accelerated biological aging in adulthood

Early-life tobacco exposure serves as a non-negligible risk factor for aging-related diseases. To understand the underlying mechanisms, we explored the associations of early-life tobacco exposure with accelerated biological aging and further assessed the joint effects of tobacco exposure and genetic susceptibility. Compared with those without in utero exposure, participants with in utero tobacco exposure had an increase in Klemera-Doubal biological age (KDM-BA) and PhenoAge acceleration of 0.26 and 0.49 years, respectively, but a decrease in telomere length of 5.34% among 276,259 participants. We also found significant dose-response associations between the age of smoking initiation and accelerated biological aging. Furthermore, the joint effects revealed that high-polygenic risk score participants with in utero exposure and smoking initiation in childhood had the highest accelerated biological aging. There were interactions between early-life tobacco exposure and age, sex, deprivation, and diet on KDM-BA and PhenoAge acceleration. These findings highlight the importance of reducing early-life tobacco exposure to improve healthy aging.

Causal factors in childhood and adolescence leading to anabolic-androgenic steroid use: A machine learning approach

Background

Prior research has demonstrated associations between anabolic-androgenic steroid (AAS) use and features from several childhood and adolescent psychosocial domains including body image concerns, antisocial traits, and low levels of parental care. However, prior approaches have been limited by their focus on individual features and lack of consideration of the relevant causal structure.

Methods

We re-analyzed data from a previous cross-sectional cohort study of 232 male weightlifters aged 18-40, of whom 101 had used AAS. These men completed retrospective measures of features from their childhood and early adolescence, including body image concerns, eating disorder psychopathology, antisocial traits, substance use, and family relationships. Using an approach informed by principles of causal inference, we applied four machine-learning methods - lasso regression, elastic net regression, random forests, and gradient boosting - to predict AAS use.

Results

The four methods yielded similar receiver operating curves, mean area under the curve (range 0.66 to 0.72), and sets of highly important features. Features related to adolescent body image concerns (especially muscle dysmorphia symptoms) were the strongest predictors. Other important features were adolescent rebellious behaviors; adolescent feelings of ineffectiveness and lack of interoceptive awareness; and low levels of paternal care.

Conclusions

Applying machine learning within a causally informed approach to re-analyze data from a prior study of weightlifters, we identified six factors (most prominently those related to adolescent body image concerns) as proposed causal factors for the development of AAS use. Compared with the prior analyses, this approach achieved greater methodologic rigor and yielded stronger and broader findings.

Social support and overeating in young women: The role of altering functional network connectivity patterns and negative emotions

Research suggests that social support has a protective effect on emotional health and emotionally induced overeating. Women are especially more sensitive to benefits from social support when facing eating problems. Although it has been demonstrated that social support can affect the neural processes of emotion regulation and reward perception, it is unclear how social support alters synergistic patterns in large-scale brain networks associated with negative emotions and overeating. We used a large sample of young women aged 17-22 years (N = 360) to examine how social support influences the synchrony of five intrinsic networks (executive control network [ECN], default mode network, salience network [SN], basal ganglia network, and precuneus network [PN]) and how these networks influence negative affect and overeating. Additionally, we explored these analyses in another sample of males (N = 136). After statistically controlling for differences in age and head movement, we observed significant associations of higher levels of social support with increased intra- and inter-network functional synchrony, particularly for ECN-centered network connectivity. Subsequent chain-mediated analyses showed that social support predicted overeating through the ECN-SN and ECN-PN network connectivity and negative emotions. However, these results were not found in men. These findings suggest that social support influences the synergistic patterns within and between intrinsic networks related to inhibitory control, emotion salience, self-referential thinking, and reward sensitivity. Furthermore, they reveal that social support and its neural markers may play a key role in young women's emotional health and eating behavior.

Relationships between birth weight discordance and maternal and perinatal risks among twin pregnancies conceived following frozen embryo transfer

STUDY QUESTION

Is intertwin birth weight discordance associated with adverse maternal and perinatal outcomes following frozen embryo transfer (FET)?

SUMMARY ANSWER

For twins conceived following FET, intertwin birth weight discordance is related to elevated risks of neonatal mortality irrespective of chorionicity, and the risk of hypertensive disorders of pregnancy (HDP) is elevated for the mothers of dichorionic twins affected by such birth weight discordance.

WHAT IS KNOWN ALREADY

While the relationships between intertwin birth weight discordance and adverse maternal or fetal outcomes have been studied for naturally conceived twins, similarly comprehensive analyses for twins conceived using ART remain to be performed.

STUDY DESIGN, SIZE, DURATION

This was a retrospective cohort study of all twin births from 2007 to 2021 at Shanghai Ninth People's Hospital in Shanghai, China that were conceived following FET (N = 6265).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Intertwin birth weight discordance was defined as a 20% difference in neonatal birth weights. The primary study outcome was the incidence of HDP and neonatal death while secondary outcomes included gestational diabetes, placenta previa, placental abruption, intrahepatic cholestasis of pregnancy, preterm premature rupture of the membranes, Cesarean delivery, gestational age, birth weight, stillbirth, birth defect, neonatal jaundice, necrotizing enterocolitis, and pneumonia incidence. Logistic regression models were used to estimate adjusted odds ratios (aORs) and 95% CIs for maternal and neonatal outcomes. Subgroup analyses were conducted, and Kaplan-Meier survival analysis was used to estimate the survival probability. The sensitivity analysis was performed with a propensity score-based patient-matching model, an inverse probability weighting model, a restricted cubic spline analysis, and logistic regression models using other percentage cutoffs for discordance.

MAIN RESULTS AND THE ROLE OF CHANCE

Of 6101 females that gave birth to dichorionic twins during the study interval, birth weight discordance was observed in 797 twin pairs (13.1%). In this cohort, intertwin birth weight discordance was related to an elevated risk of HDP (aOR 1.56; 95% CI 1.21-2.00), and this relationship was confirmed through sensitivity analyses. Hypertensive disease risk rose as the severity of this birth weight discordance increased. Discordant birth weight was also linked to increased odds of neonatal mortality (aOR 2.13; 95% CI 1.03-4.09) and this risk also increased with the severity of discordance. Of the 164 women with monochorionic twins, the discordant group exhibited an elevated risk of neonatal death compared to the concordant group (crude OR 9.00; 95% CI 1.02-79.3).

LIMITATIONS, REASONS FOR CAUTION

The limitations of this study are its retrospective nature and the fact that the available data could not specify which twins were affected by adverse outcomes. There is a lack of an established reference birth weight for Chinese twins born at a gestational age of 24-41 weeks.

WIDER IMPLICATIONS OF THE FINDINGS

These findings suggest that twins exhibiting a birth weight discordance are related to an elevated risk of adverse maternal and perinatal outcomes, emphasizing a potential need for higher levels of antenatal surveillance in these at-risk pregnancies.

STUDY FUNDING/COMPETING INTEREST(S)

Authors declare no conflict of interest. This study was funded by the Clinical Research Program of Shanghai Ninth People's Hospital affiliated to Shanghai Jiao Tong University School of Medicine (JYLJ202118) and the National Natural Science Foundation of China (Grant Nos 82271693 and 82273634).

TRIAL REGISTRATION NUMBER

N/A.

Alterations in resting-state functional activity and connectivity for major depressive disorder appetite and weight disturbance phenotypes

BACKGROUND

Major depressive disorder (MDD) is often accompanied by changes in appetite and weight. Prior task-based functional magnetic resonance imaging (fMRI) findings suggest these MDD phenotypes are associated with altered reward and interoceptive processing.

METHODS

Using resting-state fMRI data, we compared the fractional amplitude of low-frequency fluctuations (fALFF) and seed-based connectivity (SBC) among hyperphagic (n = 77), hypophagic (n = 66), and euphagic (n = 42) MDD groups and a healthy comparison group (n = 38). We examined fALFF and SBC in a mask restricted to reward [nucleus accumbens (NAcc), putamen, caudate, ventral pallidum, and orbitofrontal cortex (OFC)] and interoceptive (anterior insula and hypothalamus) regions and also performed exploratory whole-brain analyses. SBC analyses included as seeds the NAcc and also regions demonstrating group differences in fALFF (i.e. right lateral OFC and right anterior insula). All analyses used threshold-free cluster enhancement.

RESULTS

Mask-restricted analyses revealed stronger fALFF in the right lateral OFC, and weaker fALFF in the right anterior insula, for hyperphagic MDD v. healthy comparison. We also found weaker SBC between the right lateral OFC and left anterior insula for hyperphagic MDD v. healthy comparison. Whole-brain analyses revealed weaker fALFF in the right anterior insula, and stronger SBC between the right lateral OFC and left precentral gyrus, for hyperphagic MDD v. healthy comparison. Findings were no longer significant after controlling for body mass index, which was higher for hyperphagic MDD.

CONCLUSIONS

Our results suggest hyperphagic MDD may be associated with altered activity in and connectivity between interoceptive and reward regions.

Motives for spousal involvement in a Partner's diabetes management: Considering the role of gender and links to diet-related involvement

Using data from 148 middle-aged and older adult spouses whose partners had type 2 diabetes, we sought to examine spouses' motives for involvement in their partners' diabetes management and whether these motives were related to common types of diabetes-related spousal involvement; we also sought to understand gender differences in these dynamics. Spouses indicated being motivated to be involved in their partners' diabetes management due to altruistic motives to the greatest extent and egoistic motives to the least extent. Results from multivariable regression analyses that controlled for gender, marital quality, and spouses' own conditions requiring dietary changes revealed that all types of motives were related to the frequency of providing diet-related spousal support, whereas only egoistic motives were related to the frequency of exerting diet-related spousal control. We did not find gender differences in any motives nor in associations with spousal involvement. Findings have potential implications for couples-oriented chronic illness interventions.

Children's views on artificial intelligence and digital twins for the daily management of their asthma: a mixed-method study

New technologies enable the creation of digital twin systems (DTS) combining continuous data collection from children's home and artificial intelligence (AI)-based recommendations to adapt their care in real time. The objective was to assess whether children and adolescents with asthma would be ready to use such DTS. A mixed-method study was conducted with 104 asthma patients aged 8 to 17 years. The potential advantages and disadvantages associated with AI and the use of DTS were collected in semi-structured interviews. Children were then asked whether they would agree to use a DTS for the daily management of their asthma. The strength of their decision was assessed as well as the factors determining their choice. The main advantages of DTS identified by children were the possibility to be (i) supported in managing their asthma (ii) from home and (iii) in real time. Technical issues and the risk of loss of humanity were the main drawbacks reported. Half of the children (56%) were willing to use a DTS for the daily management of their asthma if it was as effective as current care, and up to 93% if it was more effective. Those with the best computer skills were more likely to choose the DTS, while those who placed a high value on the physician-patient relationship were less likely to do so.   Conclusions: The majority of children were ready to use a DTS for the management of their asthma, particularly if it was more effective than current care. The results of this study support the development of DTS for childhood asthma and the evaluation of their effectiveness in clinical trials. What is Known: • New technologies enable the creation of digital twin systems (DTS) for children with asthma. • Acceptance of these DTSs by children with asthma is unknown. What is New: • Half of the children (56%) were willing to use a DTS for the daily management of their asthma if it was as effective as current care, and up to 93% if it was more effective. •Children identified the ability to be supported from home and in real time as the main benefits of DTS.

Maternal Pre-Pregnancy Body Mass Index, Gestational Weight Gain and Children’s Cognitive Development: A Birth Cohort Study

To investigate the joint effect of maternal pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) on children’s cognitive development. We recruited 1685 mother–child pairs from the Ma’anshan Birth Cohort in China. Pre-pregnancy BMI and GWG were calculated based on the height and weights measured at multiple antenatal checkups. Children’s cognition was assessed by Wechsler Preschool and Primary Scale of Intelligence-Fourth Edition. Poisson regression model was used to analyze the association between maternal pre-pregnancy BMI and children’s cognitive dimensions under different GWG categories. Women with overweight or obese before pregnancy were more likely to obtain excessive GWG. When women had excessive GWG, pre-pregnancy overweight was associated with low children’s PSI (OR = 1.69, 95%CI: 1.02–2.81) and pre-pregnancy obesity was related to poor VCI in children (OR = 3.71, 95%CI: 1.49–9.22), after adjusting for potential confounders. In pre-pregnancy underweight mothers, adequate GWG reduced the risk of below-average VSI in children (OR = 0.22, 95%CI: 0.05–0.92), but excessive GWG was related to low FSIQ in children (OR = 2.53, 95%CI: 1.34–4.76). In women with excessive GWG, maternal pre-pregnancy BMI displays an inverted U-shape association with children’s cognition. Moreover, adequate GWG in women with pre-pregnancy underweight was beneficial for children’s cognition.

Prenatal serum thallium exposure and cognitive development among preschool-aged children: A prospective cohort study in China

Thallium, a highly toxic heavy metal and priority pollutant, has been widely reported to cause neurodevelopmental toxicity in animals. However, accessible epidemiological studies concerning the neurodevelopmental toxicity of early-life thallium exposure in humans are limited. In a prospective birth cohort including 2164 mother-child pairs, we explored the effect of prenatal serum thallium exposure on cognitive development among preschool-aged children born in Ma'anshan, Anhui, China. Serum thallium concentrations were measured in the first trimester, second trimester, third trimester, and cord blood by inductively coupled plasma mass spectrometry (ICP-MS). Child cognitive development was appraised by the Chinese version of the Wechsler Preschool and Primary Scale of Intelligence-Fourth Edition (WPPSI-IV) at 4.5 years old. Multiple informants generalized estimating equations (GEEs) were fit to jointly estimate the association between the four repeated measurements of thallium concentrations and the preschool-aged children's cognitive test scores. After adjusting for potential confounders, the visual spatial index (VSI) was 1.45 points lower in the highest tertile of serum thallium during the first trimester than in the lowest tertile (p for trend = 0.04). Moreover, children in the highest tertile of serum thallium during the third trimester had a significantly lower full-scale intelligence quotient (FSIQ) (β = -1.51, 95% CI: -2.68, -0.35), VSI (β = -1.79, 95% CI: -3.16, -0.42), fluid reasoning index (FRI) (β = -1.41, 95% CI: -2.73, -0.10), and processing speed index (PSI) (β = -1.47, 95% CI: -2.71, -0.24) scores than the children in the lowest tertile. When performing stratified analysis by child sex, the associations of first- and third-trimester thallium concentrations with cognitive test scores were more prominent in boys than in girls. Our findings revealed that maternal serum thallium exposure during the first and third trimesters, but not other periods, had detrimental effects on preschoolers' cognitive development, and these effects showed sex differences.