**Background:**
This narrative review, published in 2023, aims to analyze the factors associated with children's linear growth according to the different subsystems of the 6Cs model, which is based on Bronfenbrenner's Bioecological Theory. The theory posits that human development is influenced by interacting systems: the microsystem (immediate environment), mesosystem (interactions between microsystems), exosystem (indirect environmental influences), and macrosystem (cultural and societal values). The 6Cs model, proposed by Harrison et al., adapts this theory to health outcomes by categorizing determinants into six spheres: cell, child, clan, community, country/state, and culture. The review seeks to synthesize empirical evidence on protective and risk factors for stunting (height-for-age deficit) within this framework.
**Methods:**
The review was conducted from April to June 2022. A literature search was performed in Scielo, Lilacs, PubMed, and Science Direct databases using the terms "Bioecological Theory," "child growth," and "risk factors" combined with Boolean operators AND/OR. Inclusion criteria were empirical studies that explained children's linear growth using the height-for-age anthropometric index from an ecological perspective, analyzing potential interfering factors. Data on author/year, objective, methods, and main results were extracted and grouped according to the 6Cs model. The review included 40 studies from various countries, including Guatemala, Brazil, Peru, Indonesia, Bangladesh, India, Pakistan, Ethiopia, Rwanda, Mexico, China, Uganda, Cambodia, and the Philippines. Study designs included cross-sectional, cohort, case-control, and ecological studies.
**Key Results:**
The review identified protective and risk factors within each subsystem of the 6Cs model.
- **Cell (genetic/biological):** Low birth weight was the most frequently cited risk factor, associated with stunting in multiple studies (e.g., Rehman et al., 2009; Menezes et al., 2011; Magalhães et al., 2016; Campos et al., 2020). Prematurity, multiple births, and short birth intervals were also risk factors. Protective factors included adequate birth weight and satisfactory weight gain.
- **Child (personal/behavioral):** Male sex was identified as a risk factor (e.g., Ntenda & Chuang, 2018; Nshimyiryo et al., 2019). Age under 24 months was a risk factor due to high growth velocity. Non-exclusive breastfeeding up to the 3rd month (Musaad et al., 2016) and short duration of breastfeeding (Sk et al., 2021) were risk factors, while breastfeeding for six months or more was protective (Rachmi et al., 2016; Garcia Cruz et al., 2017). Low dietary diversity and inadequate complementary feeding were associated with stunting (e.g., Krasevec et al., 2016; Fentahun et al., 2018). Infectious diseases and anemia were also risk factors.
- **Clan (family):** Low maternal education was a consistent risk factor (e.g., Semba et al., 2008; Shang et al., 2010; Corsi et al., 2015). Short maternal stature (e.g., <150 cm in Rehman et al., 2009; <1.497 m in Silveira et al., 2020) and inadequate maternal nutritional status were risk factors. Domestic violence (Chai et al., 2016) and maternal depressive symptoms (Nasreen et al., 2013) were also associated with stunting. Protective factors included higher parental education and adequate maternal nutritional status.
- **Community:** Poor sanitation, lack of clean water, and improper hygiene practices were risk factors (e.g., Lai et al., 2022). Living in rural areas (Avan & Kirkwood, 2010; Rachmi et al., 2016) and at high altitudes (Baye & Hirvonen, 2020: an altitude increase of 1,000 m was associated with a 0.163 unit decrease in height/age index) were risk factors. Family poverty and food insecurity were strongly associated with stunting (e.g., Lee et al., 2010; Corsi et al., 2015; Campos et al., 2020).
- **Country/State:** Inadequate prenatal care (Neves et al., 2016; Ayelign & Zerfu, 2021) and lack of policies supporting nutrition were risk factors. A policy encouraging purchase of food from family farming for school meals was protective (Oliveira et al., 2022: each percentage point increase in purchase was associated with a 0.55 point decrease in stunting prevalence).
- **Culture:** No specific studies were found, but the review notes that cultural norms may influence perceptions of stunting.
**Clinical Implications:**
The review underscores that child linear growth is a multifactorial outcome requiring interventions at multiple levels. Clinically, this means that addressing stunting cannot focus solely on individual child nutrition but must also consider maternal health (education, nutrition, mental health), family environment (violence, poverty), community infrastructure (sanitation, water), and national policies (prenatal care, food security programs). The 6Cs model provides a comprehensive framework for identifying risk and protective factors, guiding targeted interventions. For example, promoting exclusive breastfeeding for six months, ensuring adequate birth weight through prenatal care, improving maternal education, and enhancing community sanitation are all evidence-based strategies. The review highlights that even in the absence of direct cultural studies, addressing systemic factors is crucial for reducing stunting and its long-term consequences on health and development.