A Multistate Model for Analyzing Transitions Between Body Mass Index Categories During Childhood: The Generation XXI Birth Cohort Study

Time-Homogeneous Markov Modeling of HIV Progression in Patients Receiving Antiretroviral Therapy Treatment in the Ashanti Region, Ghana

The global HIV/AIDS pandemic remains a profound public health challenge, with substantial impacts on mortality and morbidity worldwide. In Ghana, where HIV prevalence persists, understanding disease progression among patients receiving antiretroviral therapy (ART) is crucial. This study, conducted in the Ashanti Region, employs a 5-state continuous-time Markov multistate model to analyze HIV progression based on CD4 cell counts, employing tuberculosis (TB) coinfection as a covariate. A retrospective cohort of 416 patients from St. Martins Catholic Hospital between 2000 and 2019 was studied. Transition intensities, sojourn time and probabilities between CD4 states, and the impact of TB coinfection were evaluated. The results showed that patients with CD4 counts ≥ 500 cells/mm3 spent more time before transitioning to lower CD4 levels, indicating the effectiveness of ART in controlling the disease at this level. However, the transition from 200-350 cells/mm3 to death was more likely than recovery to CD4 counts ≥ 500 cells/mm3, indicating the increased risk of mortality once CD4 counts drop significantly. TB coinfection did not significantly alter these transition probabilities, which may be due to the effective management of both HIV and TB in this cohort, emphasizing the need for integrated care strategies. This study emphasizes the importance of tailored interventions to manage HIV/AIDS effectively, particularly in regions with high disease burden. It is recommended that initiating treatment quickly can help maintain higher CD4 counts and improve survival.

Multistate Markov chain modeling for child undernutrition transitions in Ethiopia: a longitudinal data analysis, 2002-2016

BACKGROUND

The use of the multistate Markov chain model is a valuable tool for studying child undernutrition. This allows us to examine the trends of children's transitions from one state to multiple states of undernutrition.

OBJECTIVES

In this study, our objective was to estimate the median duration for a child to first transition from one state of undernutrition to another as well as their first recurrence of undernutrition and also to analyze the typical duration of undernourishment. This involves understanding the central tendency of these transitions and durations in the context of longitudinal data.

METHODS

We used a longitudinal dataset from the Young Lives cohort study (YLCS), which included approximately 1997 Ethiopian children aged 1-15 years. These children were selected from five regions and followed through five survey rounds between 2002 and 2016. The surveys provide comprehensive health and nutrition data and are designed to assess childhood poverty. To analyze this dataset, we employed a Markov chain regression model. The dataset constitutes a cohort with repeated measurements, allowing us to track the transitions of individual children across different states of undernutrition over time.

RESULTS

The findings of our study indicate that 46% of children experienced concurrent underweight, stunting, and wasting (referred to as USW). The prevalence of underweight and stunted concurrent condition (US) was 18.7% at baseline, higher among males. The incidence density of undernutrition was calculated at 22.5% per year. On average, it took 3.02 months for a child in a wasting state to transition back to a normal state for the first time, followed by approximately 3.05 months for stunting and 3.89 months for underweight. It is noteworthy that the median duration of undernourishment among children in the US (underweight and stunted concurrently) state was 48.8 months, whereas those concurrently underweight and wasting experienced a median of 45.4 months in this state. Additionally, rural children (HR = 1.75; 95% CI: 1.53-1.97), those with illiterate fathers (HR = 1.50; 95% CI: 1.38-1.62) and mothers (HR = 1.45; 95% CI: 1.02-3.29), and those in households lacking safe drinking water (HR = 1.70; 95% CI: 1.26-2.14) or access to cooking fuel (HR = 1.95; 95% CI: 1.75-2.17) exhibited a higher risk of undernutrition and a slower recovery rate.

CONCLUSIONS

This study revealed that rural children, especially those with illiterate parents and households lacking safe drinking water but cooking fuels, face an increased risk of undernutrition and slower recovery.

Tracking changes in weight status in primary school children in Birmingham: an analysis of the National Child Measurement Programme - a retrospective cohort study

One-in-four 4-5 years and more than one-in-three 10-11 years have excess weight in England.

AIM

To identify characteristics associated with (1) having overweight, obesity and severe obesity at 11 years and (2) rapid weight gain (defined as increasing weight status by one or more body mass index (BMI) categories) between the ages of 4-5 and 10-11 years.

METHOD

Using National Child Measurement Programme data, BMI at reception (4-5 years) and year 6 (10-11 years) were linked for 15 390 children. Weight categories were identified at both time points using BMI centile classifications.For each child, the number of BMI categories they crossed between reception and year 6 was identified. Logistic regression models were fitted to explore associations with sociodemographic characteristics of children with excess weight at age 10-11 years and with children experiencing rapid weight gain between reception and year 6.

RESULTS

Overall, 61.9% of children remained in their original weight category; 30% whose weight increased by ≥1 weight categories and 11.7% by ≥2 weight categories. Only 7.8% had decreased ≥1 weight categories and 0.9% had decreased ≥2 weight categories.Adjusting for other sociodemographic characteristics, girls were less likely than boys to increase ≥2 weight categories between reception and year 6 (OR 0.64; 95% CI 0.58 to 0.71; p<0.001). Compared to white children, Asian and mixed-ethnicity children had higher odds of rapid weight gain. Children with the highest deprivation were over 6 times more likely to increase ≥2 weight categories between reception and year 6 compared with children with the lowest deprivation (OR 6.1; 95% CI 1.92 to 19.10; p<0.01).

CONCLUSION

Male children, children of Asian and mixed ethnicity and children with high deprivation are at higher risk of rapid weight gain and should be targeted for intervention.

Childhood Transitions Between Weight Status Categories: Evidence from the UK Millennium Cohort Study

BACKGROUND

Assessing the cost-effectiveness of interventions targeting childhood excess weight requires estimates of the hazards of transitioning between weight status categories. Current estimates are based on studies characterized by insufficient sample sizes, a lack of national representativeness, and untested assumptions.

OBJECTIVES

We sought to (1) estimate transition probabilities and hazard ratios for transitioning between childhood weight status categories, (2) test the validity of the underlying assumption in the literature that transitions between childhood bodyweight categories are time-homogeneous, (3) account for complex sampling procedures when deriving nationally representative transition estimates, and (4) explore the impact of child, maternal, and sociodemographic characteristics.

METHODS

We applied a multistate transition modeling approach accounting for complex survey design to UK Millennium Cohort Study (MCS) data to predict transition probabilities and hazard ratios for weight status movements for children aged 3-17. Surveys were conducted at ages 3 (wave 2 in 2004), 5 (wave 3 in 2006), 7 (wave 4 in 2008), 11 (wave 5 in 2012), 14 (wave 6 in 2015), and 17 (wave 7 in 2018) years. We derived datasets that included repeated body mass index measurements across waves after excluding multiple births and children with missing or implausible bodyweight records. To account for the stratified cluster sample design of the MCS, we incorporated survey weights and jackknife replicates of survey weights. Using a validation dataset from the MCS, we tested the validity of our models. Finally, we estimated the relationships between state transitions and child, maternal, and sociodemographic factors.

RESULTS

The datasets for our primary analysis consisted of 10,399 children for waves 2-3, 10,729 for waves 3-4, 9685 for waves 4-5, 8593 for waves 5-6, and 7085 for waves 6-7. All datasets consisted of roughly equal splits of boys and girls. Under the assumption of time-heterogeneous transition rates (our base-case model), younger children (ages 3-5 and 5-7 years) had significantly higher annual transition probabilities of moving from healthy weight to overweight (0.033, 95% confidence interval [CI] 0.026-0.041, and 0.027, 95% CI 0.021-0.033, respectively) compared to older children (0.015, 95% CI 0.012-0.018, at ages 7-11; 0.018, 95% CI 0.013-0.023, at ages 11-14; and 0.018, 95% CI 0.013-0.025 at ages 14-17 years). However, the resolution of unhealthy weight was more strongly age-dependent than transitions from healthy weight to non-healthy weight states. Transition hazards differed by child, maternal, and sociodemographic factors.

CONCLUSIONS

Our models generated estimates of bodyweight status transitions in a representative UK childhood population. Compared to our scenario models (i.e., time-homogeneous transition rates), our base-case model fits the observed data best, indicating a non-time-homogeneous pattern in transitions between bodyweight categories during childhood. Transition hazards varied significantly by age and across subpopulations, suggesting that conducting subgroup-specific cost-effectiveness analyses of childhood weight management interventions will optimize decision-making.

Meat or meatless meals at lunch and dinner – exploring the associated factors and transition between meals

This study aimed to explore the factors associated with the consumption of meat vs. meatless meals and to assess the applicability of a multi-state model to describe transitions between lunch and dinner. Fifteen thousand four hundred and eight main meals (lunch and dinner) from a sample of adults (18-84 years, n = 3852) from the Portuguese Food, Nutrition and Physical Activity Survey (IAN-AF 2015-2016) were categorised as meat, fish, ovolactovegetarian or snack. Adjusted generalised-mixed-effects models were used to explore the associations and a time-homogeneous Markov-multi-state model was applied to study the transitions. Women, older and higher educated individuals presented higher odds of consuming meatless meals and lower hazard of transitioning to meat in the following main meal. Strategies for replacing meat with more sustainable foods should be specific towards different population groups. Studying transitions across main meals, using multi-state models, can support the development of feasible, realistic and group-specific strategies to replace meat and promote dietary variety.

Transition patterns of weight status: A cohort study of Chinese school-age children

Background

Childhood overweight and obesity are increasing public concerns. However, little is known about the transition patterns of childhood weight status, especially in developing countries. In this study, we aimed to evaluate patterns of change in weight status and the risk factors among Chinese school-age children.

Methods

This retrospective cohort study included 2,334 children aged 6 years with complete 5-year (2012-2017) physical examination data in Minhang District, Shanghai. A time-homogeneous three-state Markov model was fit to the longitudinal data with dynamic outcomes (normal weight, overweight, and obesity).

Results

According to the Markov model, 42.3% of school-age children who were initially overweight transitioned to another weight status within 1 year, with 24.8% (95% confidence interval [CI]: 23.1, 27.0) transitioning to normal weight and 17.5% (95% CI: 15.9, 19.3) becoming obese. In contrast, children who were initially normal weight (92.9% [95% CI: 92.3, 93.5]) or obese (83.1% [95% CI: 81.1, 84.8]) tended to maintain their initial weight status. Male sex, semi-urban area, absence of late adiposity rebound, lower annual height increments, higher annual weight increments, and higher initial body mass index were significantly associated with a higher risk of developing or maintaining overweight and obesity (p < 0.05).

Conclusions

The weight status of Chinese school-age children is more likely to change among those who are initially overweight than in those who are initially obese. Interventions to promote healthy weight status may be more effective if key groups are targeted, such as overweight and pre-school-age children.

Do children in India grow well into adolescents? Longitudinal analysis of growth transitions from Young Lives panel survey in India

OBJECTIVES

Studies that examined the growth during late childhood and early adolescence beyond 8 years of age are very limited. Further, most studies have used dichotomized classification of stunting, thereby limiting the understanding of moderate stunting in childhood growth trajectory. We aimed to examine the course of stunting from childhood to adolescence by undertaking robust analyses of the Young Lives Survey (YLS) longitudinal data from India using multilevel categorization of stunting.

STUDY DESIGN

Retrospective cohort analysis was undertaken from YLS in India among 1827 children from the younger cohort born in 2001-02 with complete follow-up data in all five rounds of YLS collected in 2002, 2006, 2009, 2013, and 2016.

METHODS

A three-state multistate Markov model (not stunted, moderate, severe) was performed to estimate annual transition probabilities, mean sojourn-time, and transition-specific risk factors.

RESULTS

Between Round-one and Round-five, cross-sectional prevalence of severe stunting decreased from 10.4% (95% confidence interval [CI]: 7.8%, 13.7%) to 5.3% (95% CI: 3.8%, 7.3%), while moderate stunting increased from 19.9% (95% CI: 16.3%,23.9%) to 21.7% (95% CI: 18.4%, 24.9%). Mean Sojourn time estimation indicated a relatively concise state for moderate stunting. The stunting trajectory had shown gender differential where more faltering to severe stunting and lower recovery to the normal state was observed among girls between 8 and 12 years and among boys between 12 and 15 years. Compared with boys, girls had 40% excess likelihood (Hazard Ratio: 1.40; 95% CI 1.00 to 1.95) for moderate-to-severe stunting transition and also had 19% excess likelihood (Hazard Ratio: 1.19; 95% CI 1.01 to 1.40) of favorable transition (moderate-to-non-stunted).

CONCLUSIONS

The transition trajectory highlights preadolescence, especially among girls, as an additional window of opportunity to ensure better nutrition in adolescent life. With a fifth of adolescents living in India, study findings call for coordinated, multisectoral, age-appropriate, and gender-responsive approach to take India closer to meeting SDG-2.

A longitudinal analysis of the effect of maternal region-of-birth on transitions in children's bodyweight status from early childhood to late adolescence in Australia: A population-based cohort study

Although 49% of Australian residents have at least one overseas-born parent, little is known about children's longitudinal bodyweight transitions among the migrant population. This study examines the net associations between maternal region-of-birth and children's longitudinal bodyweight transitions between underweight, normal, and overweight/obese status from ages 2 to 17 years. A sample of 8889 children was drawn from seven waves of a national population-based cohort study, the Longitudinal Study of Australian Children, conducted between 2004 and 2016. A multistate approach was used to investigate (i) the net effect of mother's region-of-birth on children's bodyweight transitions, (ii) the net estimation of cumulative transition probabilities, and (ii) the net conditional bodyweight expectancy, controlling for child-, family-, and neighbourhood-factors associated with children's bodyweight. Our results showed children of Oceania and African mothers had unfavourable outcomes (i.e., lower remission from or higher incidence of underweight or overweight/obese status) than children of non-migrants. Toddlers with suboptimal bodyweight status (especially those from disadvantaged groups) had higher net cumulative probabilities of staying in that status as a 17-year-old adolescent unless they managed to transfer to normal weight in the primary school years. The 15-year bodyweight expectancy depended on the initial bodyweight status at age two years, with some children of migrant mothers affected longer by suboptimal bodyweight status. In Australia, region-of-birth related disparities in bodyweight started early and were of significant duration throughout development until late adolescence. Culturally tailored health programs should begin at least as early as two years of age.

Association between parental and offspring BMI: results from EPACI Portugal 2012

OBJECTIVE

To assess the longitudinal association between parental BMI and offspring's BMI, in EPACI Portugal 2012.

DESIGN

Longitudinal study with retrospective collection of children's anthropometry data since birth. Children's anthropometric data were gathered from individual child health bulletins, and parents' anthropometrics were self-reported. Children's and parents' BMI were classified according to WHO cut-offs. Linear mixed models with random intercept and slope for age were applied to quantify the association between parental BMI and children BMI Z-score (zBMI).

SETTING

EPACI Portugal 2012.

PARTICIPANTS

Representative sample from the Portuguese population (n 2230) aged from 12 to 36 months.

RESULTS

58·9 % of the fathers and 35·6 % of the mothers were overweight (OW) or obese. Prevalence of infants who were, at least, at risk of OW increased from 17·0 % to 30·3 % since birth to 12 months. About half of the mothers with pre-pregnancy OW and obesity (OB) gained gestational weight above the recommendations. The children from mothers with gestational weight gain (GWG) below the recommendations showed a -0·15 SD lower zBMI (95 % CI -0·23, -0·06) in early life, comparing with mothers within GWG recommendations. Children of obese mothers were more likely to present a higher zBMI (0·24 SD, 95 % CI 0·13, 0·35) throughout the first months of life.

CONCLUSIONS

A high prevalence of OW and OB was observed in Portuguese young adults and toddlers. Mothers' pre-pregnancy BMI and insufficient GWG had a direct effect on offspring BMI. Early effective interventions are needed in order to prevent the transgenerational transmission of OB.

Measuring Hypertension Progression With Transition Probabilities: Estimates From the WHO SAGE Longitudinal Study

This paper assessed the transition probabilities between the stages of hypertension severity and the length of time an individual might spend at a particular disease state using the new American College of Cardiology/American Heart Association hypertension blood pressure guidelines. Data for this study were drawn from the Ghana WHO SAGE longitudinal study, with an analytical sample of 1884 across two waves. Using a multistate Markov model, we estimated a seven-year transition probability between normal/elevated blood pressure (systolic ≤ 129 mm Hg & diastolic <80 mm Hg), stage 1 (systolic 130-139 mm Hg & diastolic 80-89 mm Hg), and stage 2 (systolic ≥140mm Hg & diastolic≥90 mm Hg) hypertension and adjusted for the individual effects of anthropometric, lifestyle, and socio-demographic factors. At baseline, 22.5% had stage 1 hypertension and 52.2% had stage 2 hypertension. The estimated seven-year transition probability for the general population was 19.0% (95% CI: 16.4, 21.8) from normal/elevated blood pressure to stage 1 hypertension, 31.6% (95% CI: 27.6, 35.4%) from stage 1 hypertension to stage 2 hypertension, and 48.5% (45.6, 52.1%) for remaining at stage 2. Other factors such as being overweight, obese, female, aged 60+ years, urban residence, low education and high income were associated with an increased probability of remaining at stage 2 hypertension. However, consumption of recommended servings of fruits and vegetables per day was associated with a delay in the onset of stage 1 hypertension and a recovery to normal/elevated blood pressure. This is the first study to show estimated transition probabilities between the stages of hypertension severity across the lifespan in sub-Saharan Africa. The results are important for understanding progression through hypertension severity and can be used in simulating cost-effective models to evaluate policies and the burden of future healthcare.

Weight transitions and psychosocial factors: A longitudinal cohort study of Finnish primary school children with overweight

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Children most probably stayed in their initial weight category.

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Probabilities of transitioning across weight categories differ between genders.

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Girls of nuclear families transition to obesity at a lower rate than their peers.

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Experiences of crises and bullying are related to obesity development among boys.

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Multistate models are useful for analyzing childhood obesity development.

For targeted prevention and treatment of childhood obesity, primary health care needs methods to identify children potentially developing obesity. The objectives of this study were to examine transitions across weight categories and their association with psychosocial family- and school-related factors, data on which were retrieved from health records. This longitudinal cohort study comprised 507 Finnish children with overweight, identified from a random sample of 2000 sixth graders in Helsinki in 2013. We applied Markov multistate models to analyze the transition rates over six primary school years between BMI SDS categories of normal weight, overweight and obesity, as assessed by Finnish BMI-for-age reference, and to examine relations between transition rates and family- and school-related factors. Among 3116 pairs of consecutive growth measurements from 225 girls and 282 boys aged 6–14, 719 transitions from weight category to another occurred. The highest 1-year probabilities were 0.76 for girls to stay in overweight and 0.80 for boys to stay in obesity. Transitions from normal weight to overweight and from obesity to overweight were more probable than vice versa. Transitions from overweight into obesity were among girls associated with older age (HR 2.63) and divorced or single parents (HR 2.29), as well as among boys with experiences of crises (HR 2.40) and being bullied (HR 1.66). Factors identifiable in school health care and associated with the probability of transition towards obesity should be considered when planning individual support and intervention programs.