This study is testing whether improving health in girls during the prepubertal period may slow the onset of puberty. This study will focus on prepubertal girls who have a high weight status (at or above the 85th percentile for body mass index). Half of the girls who join the study will participate in a treatment program to reduce weight and improve lifestyle behaviors, and half of the girls will participate in a control condition. The frequency of pubertal onset will be compared across the groups. This research is important because girls who experience puberty at an earlier age are at risk for poor psychological and physical health.

Girls in the treatment condition will participate in the Family Based Treatment (FBT) program, an established treatment for children who are overweight or obese. Families attend 20 weekly sessions (30 minutes each) over a 5-month period. Sessions are led by a trained interventionist and focus on healthy eating and physical activity behaviors.

Girls in the control condition will receive their usual medical care through their pediatric care doctor or other care provider. Families will also receive educational handouts about 1 time per month, addressing topics related to healthy eating and physical activity behaviors.

Families in both the treatment and control conditions will participate in assessments conducted at baseline and approximately 6-, 12-, 18-, 24-, 30-, and 36 months follow-up. These assessments are led by a data collector and include the measurement of height and weight, pubertal status, and health behaviors.

Abundant research shows girls who experience earlier pubertal onset exhibit substantial risk for poor outcomes in multiple areas of psychosocial functioning and physical health. At the same time, abundant research shows prepubertal body mass index (BMI) is a critical determinant of earlier pubertal onset. Integration of these research areas points to the novel focus of the proposed study which seeks to test whether an RCT targeting weight loss and positive health behavior change in the prepubertal period may slow pubertal onset in girls at risk for accelerated pubertal development. At-risk is defined as 1) being overweight/obese and 2) experiencing socioeconomic disadvantage, both factors with strong prospective links to earlier pubertal onset.

Recruitment efforts will target prepubertal girls from disadvantaged families who are overweight/obese (BMI percentile ≥85th) and ages ~6.5-8.0 years at screening with subsequent participation in the baseline assessment and randomization to the intervention/control condition. Disadvantaged families will be defined by low household income. This will be determined based on local income eligibility criteria for subsidized housing. In King County, the largest county in WA, in which the majority of subjects are expected to reside, the income requirement for subsidized housing is 80% of the area median income (AMI) adjusted for family size. This metric accounts for local variations in costing of living, which, for King County, is 58% higher than the US average. Recruitment parameters will also require at least 50% of the girls (balanced across intervention/control) will identify as Black, Latina, or 'multiple' race or ethnicity.

A total of 240 families will be randomized to the Family Based Treatment (FBT) program (n=120) vs. control condition (n=120). During a 1-2 week 'run-in' period, each family will be screened and those families who are eligible will proceed to participate in the full baseline assessment. Families who successfully complete these activities will be randomized to the FBT program vs. control condition. INTERVENTION: FBT intervention will be implemented over a 5.5-month period. Trained interventionists will lead 20 in-home, weekly sessions (30 min each) with girls and their mothers together and 20 corresponding mother-only group sessions (40 min each) online. A subset of 4 group sessions (1, 2, 10, 20) will be held in-person with both girls and their mothers attending concurrent but separate sessions. Remote sessions will be conducted via secure video-conferencing, which was tested during the COVID-19 pandemic and found to enhance session attendance. The in-home sessions (dyads) will provide protocol-based tailored support for behavioral skills related to family eating and physical activity change and will focus on feedback, accountability, and problem solving for skill use and barriers and goal-setting specific to each family. The mother-only group sessions (~6 members each) will provide education focused on behavior change as well as guidance focused on parenting in areas of healthy eating and active living. The 4 parallel child-only group sessions will provide child adapted content focused on behavior change. CONTROL: The control condition will consist of enhanced usual care. Girls randomized to this condition will receive their usual medical care through their pediatric care providers. The occurrence of these appointments will be recorded by study staff as reported through their mothers. In addition, simplified educational handouts modeled after the 20 group sessions will be sent to the families by regular mail approximately 1/month in a standard order. These handouts will resemble the content covered in the FBT program but will be exclusively knowledge-based without connection to any of the action-focused activities (e.g., goal setting) used in the intervention. Use of an enhanced usual care control condition will facilitate engagement with the families but ensure separation from the treatment elements provided through the intervention condition.

The primary intervention targets focus on positive change in weight indexed by reductions in BMI z-score (∆zBMI) and health behaviors in areas of diet quality, activity level, and sleep duration.

It is expected that the frequency of pubertal onset will be lower in girls in the intervention (vs. control) condition at the 18- and 30-month FUs (post-randomization). Pubertal onset will be indexed both by hormones and questionnaire-based pubertal staging methods to characterize the initiation of the main pubertal development processes: 1) gonadarche (i.e., luteinizing hormone [LH], Tanner stage 2 [TS2] breast) and 2) adrenarche (i.e., dehydroepiandrosterone sulfate [DHEAS], TS2 pubic hair). It is also expected that reduced zBMI and improved health behaviors will predict a lower frequency of pubertal onset at the 18- and 30-month FUs, marked by the initiation of gonadarche (LH, TS2 breast) and the initiation of adrenarche (DHEAS, TS2 pubic hair). Finally, it is expected that differences in pubertal onset will be mediated by differences in weight loss (reduced zBMI) and improved health behaviors (diet quality, activity level, sleep duration), as well as - on an exploratory basis - improved cardiometabolic health status (blood pressure, inflammation, insulin resistance), and metabolic hormones linked to adiposity and pubertal onset (leptin, IGF-1).

The clinical implications of this work are enormous. First, if slowing pubertal onset is possible, by extension, the numerous maladaptive outcomes associated with earlier pubertal onset could be reduced if not ameliorated. Moreover, girls most in need may reap the most benefit as girls from disadvantaged socioeconomic backgrounds and minoritized racial and ethnic identities are more likely to experience earlier pubertal onset. In this way, it is plausible that life course linkages between prepubertal obesity, earlier pubertal onset, and negative post-pubertal outcomes could be disrupted among those who are most vulnerable. Second, this work will inform new directions for existing obesity treatment programs in girls. Most obesity intervention and prevention efforts have not considered pubertal stage or the important intersections between obesity and pubertal onset. Findings will determine the value of conducting such interventions in this new context of slowing pubertal onset. As well, more will be learned about the optimal timing of obesity interventions, including whether implementation in the prepubertal period may be most impactful due to the combined benefits of weight loss along with a reduction in risk for earlier pubertal onset and its sequelae.

Inclusion Criteria:

1. Child female biological sex
2. Child BMI percentile in the overweight/obese range (BMI percentile ≥85th for age and sex)
3. Low child household income based on local income requirements for subsidized housing
4. At least 50% enrollment of child Black or Latina or 'multiple' race or ethnicity identification (self- or mother-identified)
5. Child between ages 6.5 and 8.0 years at screening
6. Participation of child with mother who identifies as a primary caregiver
7. Confirmed child prepubertal status by mother-report on the indicated pubertal staging scale
8. Child and mother speak English
9. Successful completion of the 'run-in' protocol, which includes screening and the baseline assessment

Exclusion Criteria:

1. Child has medical contraindications to participate in a weight loss program (e.g., chromosomal abnormality, phenylketonuria, syndromal cause of obesity, type 1 diabetes) as determined by child's pediatrician or study pediatrician
2. Mother has major medical or psychiatric conditions likely to interfere with participation (e.g., dementia, schizophrenia, terminal illness with life expectancy <12 months)
3. Family lives in temporary or group housing or has plans to relocate outside the Seattle metropolitan area in the next 12 months

Demographic, health behaviors, and health status data will be collected from 240 girls and their families. Sources of data will include anthropometrics, skin carotenoids, actigraphy, blood pressure, blood draw, acanthosis nigricans ratings, and questionnaires.

We plan to share the research data to the greatest extent possible, although there are a few considerations that will require limiting the type and amount of data shared. Certain combinations of data (geography) will not be provided due to the possibility of deducing a participant's identity.

All data will be completely de-identified prior to sharing. All identification covered under HIPAA will be removed. All remaining variables not covered under HIPAA will be evaluated in terms of the risk of deductive disclosure of identity, and measures will be taken to protect confidentiality. Data sharing plans will be fully described in the informed consent documents for the study.

Data will be made available as soon as possible after the data collection period has ended and will occur no later than the end of the project period or the time of any publication. Data will remain available for a period of at least 10 years, or indefinitely if possible.

The project generated data and metadata will be archived in the OSF, an NIH-recommended generalist repository, member of the NIH Generalist Repository Ecosystem Initiative (GREI), which meets the NIH's Desirable Characteristics for Data Repositories.

As a public dataset on OSF, the data will receive a persistent identifier through registration of a DOI with Datacite, and with rich metadata using the Datacite metadata schema. The metadata for the OSF data will follow the OSF metadata profile, which maps to the Datacite community-developed metadata schema, which includes title, description, authors, license, subject, language, resource type, publication date, modification date.

Access to the OSF public log data is made accessible through the OSF API which is licensed under Apache 2.0 and in the public domain for use.