Factors Associated With Changes in Weight-status in Danish School Children With Obesity
Condition: Pediatric Obesity
MeSH terms: Obesity; Pediatric Obesity
Study type: Observational [Patient Registry]

Summary: 
      Childhood obesity is increasing worldwide and causes a major health concern. Only limited
      insight exists into the natural history of childhood obesity at children already classified
      as obese. It is necessary to identify possible windows of opportunities to initiate treatment
      and to prevent further weight gain later in life.

      This observational study follows the natural weight change in younger children with obesity
      without known intervention. The objective is to identify factors associated with achieving
      normal weight, having persistent obesity, or reaching higher levels of obesity, when
      following children age 5-10 years with obesity through childhood and puberty.

      Data from health check-ups at school and Danish registries will be used to answer the
      research question.
    

Detailed description: 
      Only limited insight exists into the natural history of childhood obesity at children already
      classified as obese. It is necessary to identify possible windows of opportunities to
      initiate treatment and to prevent further weight gain later in life.

      High Body Mass Index (BMI) or weight status early in life seems to predict the risk of
      persisting obesity and indicating BMI as an important predictor for the chance of remission.
      High birthweight has also been associated with poor chance of normalizing weight, when
      following children with obesity from kindergarten to the 8th grade, indicating that severe
      obesity can be detectable from early childhood.

      Children with severe obesity (iso-BMI ≥ 35) have been observed to gain weight with a faster
      rate and with a critical period between 12 to 14 years of age, compared to children with
      less-severe obesity (iso-BMI < 35). Another report observes, that having obesity at the age
      of six was associated with obesity after puberty, while no such association was observed for
      younger children (six years). Hereby suggesting that children at a younger age have chance of
      achieving remission of obesity, than children classified as having obesity later in life.

      Other factors such as sex, ethnicity and interpersonal skills have also been observed to
      influence the chance of normalizing weight, when following children with obesity from 5th to
      8th grade.

      This study aims to identify factors associated with achieving normal weight, when following
      children age 5-10 yrs. with obesity through childhood and puberty.

      In addition, to identify factors associated with having persisting obesity, or reaching a
      higher level of obesity (highest 20% increase in BMI z-score from baseline)

      The participants:

      This study includes Danish children 5 to 10 years of age with obesity with minimum three
      years of follow-up during. Children invited into the local community-based lifestyle
      intervention will be excluded. The IOTF cut-offs for weight status at the last obtained
      observation will be used to define the groups.

      Data sources:

        1. Observations containing anthropometrics have been extracted from TM-Sund for each child.
           TM-Sund is a database used in Aarhus municipality to store data on anthropomet-rics
           obtained at health checks at the school (read more on https://www.solteq.com/da).

        2. Data on family structure, socioeconomic status (SES), immigration status and psychiatric
           diagnoses (child and parents) will be obtained from Danish registries at Statistics
           Den-mark.

        3. The local registry at Aarhus Municipality will be used to identify and exclude children
           1) treated in or 2) declined participation in a lifestyle intervention.

      Statistics:

      A logistic regression analysis will be used to identify baseline factors associated with the
      group of children normalizing weight, persistent obesity and highest increase of BMI z-score
      (above the 20th centile) at the last observation, respectively. Observations will be weighted
      by the possible follow-up.

      Ethics & permissions:

      The Danish Data Protection Agency and the local committee on health ethics have approved the
      overall project and data transfer (rec.no 1-45-70-27-2).
    

Intervention name(s): Change of weight class to normal weight
Intervention type(s): Other
Intervention description(s): The exposure is the change of weight class from obesity to normal weight during a follow-up period without known intervention.
Observational model: Cohort
Time perspective: Other
Sampling method: Non-Probability Sample
Study population: 
        The population consist of children with obesity from the city of Aarhus, Denmark between
        January 1st 2010 and March 18nd 2018, but followed until March 18nd 2021.
      
Keywords: Weight Loss; Body-Weight Trajectory