The investigators will conduct a case-control study among under-two children in Lombok Timur, West Nusa Tenggara, Indonesia. The power required to detect changes in epigenetic markers may not be sufficient in the cohort study. Therefore, specific case-control design of stunted vs non-stunted children will provide the required power to detect potential epigenetic markers which will be further investigated through targeted sequencing of the cohort study. A total of 150 stunted children will be recruited and then it will be matched with 150 non-stunted children with the same sex. The assessments for these study subjects will include: 1) The genetic and epigenetic profile of the children, gut microbiota and nutritional status (Physical component), 2) Food security, Water, Sanitation and Hygiene (WASH) and Infant and Young Child Feeding (IYCF) practices (Home-Food component), 3) Children's psychosocial care and cognitive outcome (Cognition component).

This study is part of Action Against Stunting Hub, an observational cohort study aimed to build evidence based on exploring the drivers of stunting from different perspectives and understand the impact of different interventions across three countries: India, Indonesia and Senegal. This study is intended to give the overview of stunting and its determinants among under-two children growing up during period of Covid-19 pandemic in Lombok Timur, Nusa Tenggara Barat, Indonesia. Because, the power required to detect changes in epigenetic markers may not be sufficient in the cohort study, this specific case-control design of stunted vs non-stunted children will also provide the required power to detect potential epigenetic markers which will be further investigated through targeted sequencing of the cohort study. The results of this initial study are projected to support further study, especially the observational cohort study, in determining the best suited indicators to prove the interaction and/or causal mechanisms of stunting.

Inclusion Criteria:

• aged 18.0 - 23.9 months
• without serious illnesses
• the mother delivered the children between 18-40 years of age
• has Sasak ethnicity, (5) recumbent length <-2SD (for stunted group) and >-1SD (for non- stunted group) from the WHO Child Growth Standards median for their age and sex at the recruitment.

Exclusion Criteria:

• twin birth
• congenital malformation
• consanguinity

A total of 150 stunted children (case) will be recruited and then it will be matched with 150 non-stunted children (control) with the same sex. Before the screening time, data of children aged 18.0-23.9 months from Posyandu will be listed. The field team will coordinate with midwives to inform the children and their guardian to get screened. Screening for eligibility criteria will be done for all children aged 18.0-23.9 months that has listed in the previous visit. Length measurement for the children and checklist of eligibility criteria will be done during the screening time by trained enumerators. After fulfilling the eligibility criteria, the enumerators have to determine to matched children based on their gender.