Long-term Academic and Psychosocial Impact of Child's Sleep: Parental Influences

Sleep Clinical Trial

Official title:

Long-term Academic and Psychosocial Impact of Child's Sleep: Parental Influences

Clinical Trial Details — Status: Active, not recruiting

Administrative data

• NCT number: NCT05049499
• Other study ID #: LAPICS
• Status: Active, not recruiting
• Start date: January 8, 2021
• Est. completion date: December 31, 2025

Study information

• Verified date: November 2023
• Source: National University of Singapore
• Contact: n/a
• Is FDA regulated: No
• Study type: Observational

Clinical Trial Summary

The proposed longitudinal project aims to understand parental influences on children's sleep and will investigate the effect of sleep-related parental factors - (1) parents' value of their children's sleep relative to other activities, (2) parental involvement in setting children's sleep habits and enforcing good sleep hygiene, and (3) parent's own sleep habits - on school-age children's sleep, mental health, socio-emotional resilience, and academic/cognitive performance. It will also investigate the impact of social economic status on these sleep -related parental factors.

Description:

Parents can influence their children's sleep in various ways. However, existing studies on parental factors of school-aged children's sleep have seldom moved beyond sleep hygiene and the relationships between parent and child's sleep patterns. A potential factor that has been overlooked is parents' value of their children's sleep - whether they value their children's sleep and prioritise it over other activities, e.g. studying or watching TV. Another variable to consider is the social economic status (SES) of the household, which can influence these parental factors. The proposed longitudinal project will investigate the impact of SES on several sleep-related parental factors and the effects these parental factors have on children's sleep, mental health, socio-emotional resilience, and academic/cognitive performance. The project will involve school-age children in Singapore (baseline age: 7-12 years) at two time points, time 1 (T1) and time 2 (T2), one year apart. At each timepoint, children's sleep will be assessed with actigraphy for 1 school week. This will be followed by a lab visit during which sleep-related parental factors, as well as the children's sleep, academic and cognitive performance, socio-emotional resilience, and mental health will be assessed. Lab visits will be scheduled at the end of the school week in the morning and early afternoon so that neurobehavioural functions can be captured during typical school hours. Investigators hypothesise that parents from low SES households will value their child's sleep less, and therefore, allow their child to trade a larger amount of sleep for other activities. Parents from low SES households will also enforce good sleep hygiene less, and sleep less themselves. Children from low SES households will thus have shorter sleep duration, more sleep disturbance, poorer mental health, poorer socio-emotional resilience, and poorer academic and cognitive performance.

Recruitment information / eligibility

• Status: Active, not recruiting
• Enrollment: 150
• Est. completion date: December 31, 2025
• Est. primary completion date: September 30, 2024
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 7 Years to 12 Years

Eligibility

Inclusion Criteria:

• Is aged between 7 and 12 years
• Is a Singaporean
• Is English-speaking
• Is not on any long-term medications
• Has no known medical conditions that could affect sleep (e.g. asthma)
• Has no history of psychiatric or neurological disorders
• Has no history of sleep problems / disorders Exclusion Criteria: The reverse of the inclusion criteria

Related Conditions & MeSH terms

• Mental Well-being
• Parents
• School-age Children
• Sleep

Locations

Country	Name	City	State
Singapore	National University of Singapore	Singapore

Sponsors (1)

Lead Sponsor	Collaborator
National University of Singapore

Country where clinical trial is conducted

Singapore, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Number of minutes of sleep allowed to be traded for studying on weekdays	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for studying (including homework and tuition) on weekdays	At year 1
Primary	Number of minutes of sleep allowed to be traded for studying on weekdays	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for studying (including homework and tuition) on weekdays	At year 2
Primary	Number of minutes of sleep allowed to be traded for studying on weekends	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for studying (including homework and tuition) on weekends	At year 1
Primary	Number of minutes of sleep allowed to be traded for studying on weekends	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for studying (including homework and tuition) on weekends	At year 2
Primary	Number of minutes of sleep allowed to be traded for co-/extra-curricular activities on weekdays	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for co-/extra-curricular activities on weekdays	At year 1
Primary	Number of minutes of sleep allowed to be traded for co-/extra-curricular activities on weekdays	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for co-/extra-curricular activities on weekdays	At year 2
Primary	Number of minutes of sleep allowed to be traded for co-/extra-curricular activities on weekends	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for co-/extra-curricular activities on weekends	At year 1
Primary	Number of minutes of sleep allowed to be traded for co-/extra-curricular activities on weekends	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for co-/extra-curricular activities on weekends	At year 2
Primary	Number of minutes of sleep allowed to be traded for interacting face to face with family / friends on weekdays	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for interacting face to face with family / friends on weekdays	At year 1
Primary	Number of minutes of sleep allowed to be traded for interacting face to face with family / friends on weekdays	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for interacting face to face with family / friends on weekdays	At year 2
Primary	Number of minutes of sleep allowed to be traded for interacting face to face with family / friends on weekends	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for interacting face to face with family / friends on weekends	At year 1
Primary	Number of minutes of sleep allowed to be traded for interacting face to face with family / friends on weekends	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for interacting face to face with family / friends on weekends	At year 2
Primary	Number of minutes of sleep allowed to be traded for social media on weekdays	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for social media on weekdays	At year 1
Primary	Number of minutes of sleep allowed to be traded for social media on weekdays	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for social media on weekdays	At year 2
Primary	Number of minutes of sleep allowed to be traded for social media on weekends	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for social media on weekends	At year 1
Primary	Number of minutes of sleep allowed to be traded for social media on weekends	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for social media on weekends	At year 2
Primary	Number of minutes of sleep allowed to be traded for gaming on weekdays	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for gaming on weekdays	At year 1
Primary	Number of minutes of sleep allowed to be traded for gaming on weekdays	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for gaming on weekdays	At year 2
Primary	Number of minutes of sleep allowed to be traded for gaming on weekends	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for gaming on weekends	At year 1
Primary	Number of minutes of sleep allowed to be traded for gaming on weekends	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for gaming on weekends	At year 2
Primary	Number of minutes of sleep allowed to be traded for watching TV / videos on weekdays	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for watching TV / videos on weekdays	At year 1
Primary	Number of minutes of sleep allowed to be traded for watching TV / videos on weekdays	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for watching TV / videos on weekdays	At year 2
Primary	Number of minutes of sleep allowed to be traded for watching TV / videos on weekends	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for watching TV / videos on weekends	At year 1
Primary	Number of minutes of sleep allowed to be traded for watching TV / videos on weekends	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for watching TV / videos on weekends	At year 2
Primary	Number of minutes of sleep allowed to be traded for other activities (non-listed) on weekdays	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for other activities (not already listed above) on weekdays	At year 1
Primary	Number of minutes of sleep allowed to be traded for other activities (non-listed) on weekdays	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for other activities (not already listed above) on weekdays	At year 2
Primary	Number of minutes of sleep allowed to be traded for other activities (non-listed) on weekends	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for other activities (not already listed above) on weekends	At year 1
Primary	Number of minutes of sleep allowed to be traded for other activities (non-listed) on weekends	Parents will indicate the number of minutes they allow their child to sleep less in exchange for more time for other activities (not already listed above) on weekends	At year 2
Primary	Parent-set bedtime on weekdays	Parents will indicate whether they allow their children to decide their own bedtimes on weekdays	At year 1
Primary	Parent-set bedtime on weekdays	Parents will indicate whether they allow their children to decide their own bedtimes on weekdays	At year 2
Primary	Parent-set bedtime on weekends	Parents will indicate whether they allow their children to decide their own bedtimes on weekends	At year 1
Primary	Parent-set bedtime on weekends	Parents will indicate whether they allow their children to decide their own bedtimes on weekends	At year 2
Primary	Parent-set wake time on weekdays	Parents will indicate whether they allow their children to decide their own wake times on weekdays	At year 1
Primary	Parent-set wake time on weekdays	Parents will indicate whether they allow their children to decide their own wake times on weekdays	At year 2
Primary	Parent-set wake time on weekends	Parents will indicate whether they allow their children to decide their own wake times on weekends	At year 1
Primary	Parent-set wake time on weekends	Parents will indicate whether they allow their children to decide their own wake times on weekends	At year 2
Primary	Child's usage of electronic device 1 hour before bedtime	Parents will indicate whether their child uses any electronic device 1 hour before going to bed	At year 1
Primary	Child's usage of electronic device 1 hour before bedtime	Parents will indicate whether their child uses any electronic device 1 hour before going to bed	At year 2
Primary	Noise during child's sleep time	Questions include: Is your home noisy during his/her sleep time? (Not noisy, A little noisy, Noisy) Does your child take his/her phone into the bedroom close to bed time? (Yes, No, N.A) Does your child put his/her phone on silent mode or switch it off before going to bed? (Yes, No, N.A.)	At year 1
Primary	Noise during child's sleep time	Questions include: Is your home noisy during his/her sleep time? (Not noisy, A little noisy, Noisy) Does your child take his/her phone into the bedroom close to bed time? (Yes, No, N.A) Does your child put his/her phone on silent mode or switch it off before going to bed? (Yes, No, N.A.)	At year 2
Primary	Temperature in the bedroom during child's sleep time	Questions include: Is any of the following cooling devices used in his/her room during his/her sleep time? (Air conditioner, Electric fan, Both air conditioner and electric fan, Neither air conditioner nor electric fan) What is the average temperature of his/her room during his/her sleep time? (°C)	At year 1
Primary	Temperature in the bedroom during child's sleep time	Questions include: Is any of the following cooling devices used in his/her room during his/her sleep time? (Air conditioner, Electric fan, Both air conditioner and electric fan, Neither air conditioner nor electric fan) What is the average temperature of his/her room during his/her sleep time? (°C)	At year 2
Primary	Darkness of the bedroom during child's sleep time	Questions include: How dark is his/her room during his/her sleep time? (1. Very bright, 2. Moderately bright, 3. Average, 4. Moderately dark, 5. Entirely or almost entirely dark) If your child's bedroom is not completely dark during bedtime, what are the types of light source that are present in his/her bedroom? (The bedroom is completely dark, Room light / Nightlight, Light from another room inside the house, Light from outside the house)	At year 1
Primary	Darkness of the bedroom during child's sleep time	Questions include: How dark is his/her room during his/her sleep time? (1. Very bright, 2. Moderately bright, 3. Average, 4. Moderately dark, 5. Entirely or almost entirely dark) If your child's bedroom is not completely dark during bedtime, what are the types of light source that are present in his/her bedroom? (The bedroom is completely dark, Room light / Nightlight, Light from another room inside the house, Light from outside the house)	At year 2
Primary	Child's daily caffeine consumption	Parents will indicate the average amount of caffeine their child typically consumes each day.	At year 1
Primary	Child's daily caffeine consumption	Parents will indicate the average amount of caffeine their child typically consumes each day.	At year 2
Primary	Parents' work schedule assessed by what time parent's leave for work	Parents will report the time they usually leave the house for work.	At year 1
Primary	Parents' work schedule assessed by what time parent's leave for work	Parents will report the time they usually leave the house for work.	At year 2
Primary	Parents' work schedule assessed by what time parent's reach home	Parents will report the time they usually reach home after work.	At year 1
Primary	Parents' work schedule assessed by what time parent's reach home	Parents will report the time they usually reach home after work.	At year 2
Primary	Parents' bedtime on weekdays	Parents will report the time they usually go to bed on weekdays.	At year 1
Primary	Parents' bedtime on weekdays	Parents will report the time they usually go to bed on weekdays.	At year 2
Primary	Parents' bedtime on weekends	Parents will report the time they usually go to bed on weekends.	At year 1
Primary	Parents' bedtime on weekends	Parents will report the time they usually go to bed on weekends.	At year 2
Primary	Parents' wake time on weekdays	Parents will report the time they usually wake up on weekdays.	At year 1
Primary	Parents' wake time on weekdays	Parents will report the time they usually wake up on weekdays.	At year 2
Primary	Parents' wake time on weekends	Parents will report the time they usually wake up on weekends.	At year 1
Primary	Parents' wake time on weekends	Parents will report the time they usually wake up on weekends.	At year 2
Primary	Parents' sleep duration on weekdays	Parents will report their usual sleep duration on weekdays.	At year 1
Primary	Parents' sleep duration on weekdays	Parents will report their usual sleep duration on weekdays.	At year 2
Primary	Parents' sleep duration on weekends	Parents will report their usual sleep duration on weekends.	At year 1
Primary	Parents' sleep duration on weekends	Parents will report their usual sleep duration on weekends.	At year 2
Primary	Child's time in bed as measured by actigraphy	Participants will wear an actiwatch (Actiwatch 2, Philips Respironics) around the wrist of their non-dominant hand for one week during school term. Data will be collected at 30-second resolution.	At year 1
Primary	Child's time in bed as measured by actigraphy	Participants will wear an actiwatch (Actiwatch 2, Philips Respironics) around the wrist of their non-dominant hand for one week during school term. Data will be collected at 30-second resolution.	At year 2
Primary	Child's total sleep time as measured by actigraphy	Participants will wear an actiwatch (Actiwatch 2, Philips Respironics) around the wrist of their non-dominant hand for one week during school term. Data will be collected at 30-second resolution.	At year 1
Primary	Child's total sleep time as measured by actigraphy	Participants will wear an actiwatch (Actiwatch 2, Philips Respironics) around the wrist of their non-dominant hand for one week during school term. Data will be collected at 30-second resolution.	At year 2
Primary	Child's sleep efficiency as measured by actigraphy	Participants will wear an actiwatch (Actiwatch 2, Philips Respironics) around the wrist of their non-dominant hand for one week during school term. Data will be collected at 30-second resolution.	At year 1
Primary	Child's sleep efficiency as measured by actigraphy	Participants will wear an actiwatch (Actiwatch 2, Philips Respironics) around the wrist of their non-dominant hand for one week during school term. Data will be collected at 30-second resolution.	At year 2
Primary	Child's subjective sleep quality	Participants will report their subjective sleep quality using an item modified from the Pittsburgh Sleep Quality Index - "How would you rate the quality of your sleep last night?" ("Very good" / "Fairly good" / "Fairly bad" / "Very bad").	At year 1
Primary	Child's subjective sleep quality	Participants will report their subjective sleep quality using an item modified from the Pittsburgh Sleep Quality Index - "How would you rate the quality of your sleep last night?" ("Very good" / "Fairly good" / "Fairly bad" / "Very bad").	At year 2
Primary	Child's bedtime on weekdays as reported by parents	Parents will report their child's usual bedtime on weekdays.	At year 1
Primary	Child's bedtime on weekdays as reported by parents	Parents will report their child's usual bedtime on weekdays.	At year 2
Primary	Child's bedtime on weekends as reported by parents	Parents will report their child's usual bedtime on weekends.	At year 1
Primary	Child's bedtime on weekends as reported by parents	Parents will report their child's usual bedtime on weekends.	At year 2
Primary	Child's wake time on weekdays as reported by parents	Parents will report their child's usual wake time on weekdays.	At year 1
Primary	Child's wake time on weekdays as reported by parents	Parents will report their child's usual wake time on weekdays.	At year 2
Primary	Child's wake time on weekends as reported by parents	Parents will report their child's usual wake time on weekends.	At year 1
Primary	Child's wake time on weekends as reported by parents	Parents will report their child's usual wake time on weekends.	At year 2
Primary	Child's sleep duration on weekdays as reported by parents	Parents will report their child's usual sleep duration on weekdays.	At year 1
Primary	Child's sleep duration on weekdays as reported by parents	Parents will report their child's usual sleep duration on weekdays.	At year 2
Primary	Child's sleep duration on weekends as reported by parents	Parents will report their child's usual sleep duration on weekends.	At year 1
Primary	Child's sleep duration on weekends as reported by parents	Parents will report their child's usual sleep duration on weekends.	At year 2
Primary	Frequency of child's sleep-related problems	The sum of the reported frequency (0 = never; 1 = < 1 time per month, 2 = 1-2 times per month, 3 = 1-2 times per week, 4 = = 3 times per week) at which their child experiences various sleep-related problems. Statements/questions include: Difficulty falling asleep; Anxious or afraid when falling asleep; Repetitive rocking movements or head banging while falling asleep; Startled or jerky movements of body parts while asleep; Sweating frequently during the night; Sudden awakening during sleep; Breathing difficulty during sleep; Mouth breathing during sleep; Breath holding or pausing during sleep; Lips turning blue while asleep; Frequent position changes while asleep Sleeping in prone position with buttocks up and neck extended; Teeth grinding during sleep; Bed wetting during sleep; Sleep talking; Nightmares; Waking up in the early morning and unable to fall back asleep; Dry mouth in the morning; Did he/she have any other sleep problems?	At year 1
Primary	Frequency of child's sleep-related problems	The sum of the reported frequency (0 = never; 1 = < 1 time per month, 2 = 1-2 times per month, 3 = 1-2 times per week, 4 = = 3 times per week) at which their child experiences various sleep-related problems. Statements/questions include: Difficulty falling asleep; Anxious or afraid when falling asleep; Repetitive rocking movements or head banging while falling asleep; Startled or jerky movements of body parts while asleep; Sweating frequently during the night; Sudden awakening during sleep; Breathing difficulty during sleep; Mouth breathing during sleep; Breath holding or pausing during sleep; Lips turning blue while asleep; Frequent position changes while asleep Sleeping in prone position with buttocks up and neck extended; Teeth grinding during sleep; Bed wetting during sleep; Sleep talking; Nightmares; Waking up in the early morning and unable to fall back asleep; Dry mouth in the morning; Did he/she have any other sleep problems?	At year 2
Primary	Sustained attention assessed with the 5-minute Psychomotor Vigilance Task	Number of attention lapses (>500ms)	At year 1
Primary	Sustained attention assessed with the 5-minute Psychomotor Vigilance Task	Number of attention lapses (>500ms)	At year 2
Primary	Median reaction time assessed with the 5-minute Psychomotor Vigilance Task	Median reaction time	At year 1
Primary	Median reaction time assessed with the 5-minute Psychomotor Vigilance Task	Median reaction time	At year 2
Primary	Standard deviation of reaction time assessed with the 5-minute Psychomotor Vigilance Task	Standard deviation of reaction time	At year 1
Primary	Standard deviation of reaction time assessed with the 5-minute Psychomotor Vigilance Task	Standard deviation of reaction time	At year 2
Primary	Child's academic performance	Parents will respond to two questions: "how well do you feel your child is performing at school" and "combining across all subjects, what is your child's typical overall grade in school".	At year 1
Primary	Child's academic performance	Parents will respond to two questions: "how well do you feel your child is performing at school" and "combining across all subjects, what is your child's typical overall grade in school".	At year 2
Primary	Child's daytime sleepiness	Child's daytime sleepiness will be indicated by the total score of the Pediatric Daytime Sleepiness Scale.	At year 1
Primary	Child's daytime sleepiness	Child's daytime sleepiness will be indicated by the total score of the Pediatric Daytime Sleepiness Scale.	At year 2
Primary	Child's socio-emotional resilience assessed by the child's ability to accept responsibility and to regulate his/her emotion	Parents will fill in the Social-Emotional Assets and Resilience Scales-Parent form (SEARS-P), which consists of 39 items. The total score of each subscale will be used to respectively indicate the child's ability to regulate his / her emotion and accept responsibility, make friends, and empathise.	At year 1
Primary	Child's socio-emotional resilience assessed by the child's ability to accept responsibility and to regulate his/her emotion	Parents will fill in the Social-Emotional Assets and Resilience Scales-Parent form (SEARS-P), which consists of 39 items. The total score of each subscale will be used to respectively indicate the child's ability to regulate his / her emotion and accept responsibility, make friends, and empathise.	At year 2
Primary	Child's socio-emotional resilience assessed by the child's ability to make friends	Parents will fill in the Social-Emotional Assets and Resilience Scales-Parent form (SEARS-P), which consists of 39 items. The total score of each subscale will be used to respectively indicate the child's ability to regulate his / her emotion and accept responsibility, make friends, and empathise.	At year 1
Primary	Child's socio-emotional resilience assessed by the child's ability to make friends	Parents will fill in the Social-Emotional Assets and Resilience Scales-Parent form (SEARS-P), which consists of 39 items. The total score of each subscale will be used to respectively indicate the child's ability to regulate his / her emotion and accept responsibility, make friends, and empathise.	At year 2
Primary	Child's socio-emotional resilience assessed by the child's ability to empathise	Parents will fill in the Social-Emotional Assets and Resilience Scales-Parent form (SEARS-P), which consists of 39 items. The total score of each subscale will be used to respectively indicate the child's ability to regulate his / her emotion and accept responsibility, make friends, and empathise.	At year 1
Primary	Child's socio-emotional resilience assessed by the child's ability to empathise	Parents will fill in the Social-Emotional Assets and Resilience Scales-Parent form (SEARS-P), which consists of 39 items. The total score of each subscale will be used to respectively indicate the child's ability to regulate his / her emotion and accept responsibility, make friends, and empathise.	At year 2
Primary	Child's depression symptoms	Parents will report the frequency at which their child experiences each of the 10 depression symptoms on the 25-item Revised Child Anxiety and Depression Scale.	At year 1
Primary	Child's depression symptoms	Parents will report the frequency at which their child experiences each of the 10 depression symptoms on the 25-item Revised Child Anxiety and Depression Scale.	At year 2
Primary	Child's anxiety symptoms	Parents will report the frequency at which their child experiences each of the 15 anxiety symptoms on the 25-item Revised Child Anxiety and Depression Scale.	At year 1
Primary	Child's anxiety symptoms	Parents will report the frequency at which their child experiences each of the 15 anxiety symptoms on the 25-item Revised Child Anxiety and Depression Scale.	At year 2
Primary	Child's internalising behaviour	Parents will complete the Child Behaviour Checklist that assesses their child's internalising behaviour at Time 1	At year 1
Primary	Child's internalising behaviour	Parents will complete the Child Behaviour Checklist that assesses their child's internalising behaviour at Time 2	At year 2
Primary	Child's externalising behaviour	Parents will complete the Child Behaviour Checklist that assesses their child's externalising behaviour at Time 1.	At year 1
Primary	Child's externalising behaviour	Parents will complete the Child Behaviour Checklist that assesses their child's externalising behaviour at Time 2	At year 2
Primary	Child's age	Parents will report child's age at Time 1	At year 1
Primary	Child's age	Parents will report child's age at Time 2	At year 2
Primary	Child's gender	Parents will report child's gender.	At year 1
Primary	Child's ethnicity	Parents will report child's ethnicity.	At year 1
Primary	Parents' age	Parents will report their ages at Time 1	At year 1
Primary	Parents' age	Parents will report their ages at Time 2	At year 2
Primary	Parents' education level	Parents will report their education level at Time 1	At year 1
Primary	Parents' education level	Parents will report their education level at Time 2	At year 2
Primary	Parents' marital status	Parents will report their marital status at Time 1	At year 1
Primary	Parents' marital status	Parents will report their marital status at Time 2	At year 2
Primary	Socioeconomic status assessed by the type of accommodation	Parents will report the type of accommodation they are living in at Time 1	At year 1
Primary	Socioeconomic status assessed by the type of accommodation	Parents will report the type of accommodation they are living in at Time 2	At year 2
Primary	Socioeconomic status assessed by monthly household income	Parents will report their monthly household income at Time 1	At year 1
Primary	Socioeconomic status assessed by monthly household income	Parents will report their monthly household income at Time 2	At year 2