Association Between Short Sleep Duration And Body Mass Index In Australian Children: A Systematic Review

Background to Proposed Study

To protect lives and eliminate the risk factor for cardiovascular, metabolic dysfunctions in native and energising technology to discover the cure.

Evidence suggests a clear link between an inverse relation between sleep duration and obesity along with a direct association between obesity and chronic metabolic disorders. Obese children have increased probability of becoming obese adults. There is lack of data about sleep duration and quality for Indigenous Australian people. It is assumed as a possibility that poor-quality, short sleep is one of the causes of the gap in health outcomes for nativechildrenas compared to non-native children in Australia.

The causal factors of childhood overweight and obesity are topic research across the world (Han, et al., 2010). Recent research have revealed that children who do not sleep for sufficient hours have increased chances to have high Body Mass Index, waist circumference and obesity rates (Jarrin, et al., 2013). The most common recommended guidelines is that children between five and 12 years of age must get 9 to 11 hours of sleep (Australian Sleep Health Foundation, 2011). The average sleeping duration of children has reduced across the globe in past years (Matricciani, et al., 2012). Particularly, the data from Australia has reported a decrease in average sleep time of about 28 minutes and 33 minutes for female and male Australian children respectively between 1985 and 2004 (Dollman, et al., 2007). The decline in average sleep duration has taken place along with another global trend of increasing prevalence of obesity. Several researches including studies of Australian children have established and confirmed the link between obesity with lack of sufficient sleep, declined physical activity and increased sedentary lifestyle.

The association between sleep duration and Body Mass Index in native children has significant implications for their future health outcomes. Obese and sleep deprived conditions are verified as modifiable risk factors for metabolic impairment and other chronic disordersprevalent in the native population. It is essential to build strategies to improve health outcomes and life expectancy for native children to ‘close the gap’ between native and non-native people.Short sleep duration has been identified as an independent risk factor for subsequent obesity and weight gain(Patel & Hu, 2008). Obesity has been found as an independent risk factor for development of various chronic risk factors(Boodai, et al., 2014). This systematic review of the literature is done to examine the evidence suggesting the relationship between sleep duration and subsequent weight gain among native children will be identified along with the possible mechanisms of the relationship.

Aim- This study aims to close the gap between native and non-native children of Australia by improving their health outcomes and life expectancy by identifying the mechanisms of sleep duration-obesity association and building preventive interventions based on those findings.

H0- Children who do not take adequate recommended sleep will have more chances of being overweight and obese and lower daily physical activity and increased sedentary time as compared to the children who take sufficient sleep.

H1- Eating schedule, dietary intake, obesogenic eating habits, and alterations in appetite-regulating hormones are likely to be the mechanisms for sleep–obesity associations.

Hypothesis and Aims

Research process

Research strategy

A systematic review of the literature in will be conducted.Relevant original articles were identified by searching the MEDLINE,PubMed and other databases of articles published between 2008 and 2018 in English. Articles which investigated the association between sleep duration and weight gain, obesity or both were considered. Keywords used for primary search were “sleep” and “duration” “obesity”, “overweight”,  “children”, “body weight” along with the usage of Boolean operators(AND, OR). Another search was conducted subsequently using medical subheading (MeSH). Also, for the research, Google Scholar was researched. Reference lists of the retrieved articles were reviewed manually. In cases, where findings from the same cohort were stated in multiple articles, the report which evaluated the sleep-weight association and its mechanisms most directly was taken in the review. After the selection of the articles, their abstracts were screened to ascertain relevant articles. Next, the articles were analysed for presentation of data about the relationship between sleep duration and any measure of weight such as BMI, weight, etc.

The literature will be reviewed by the author of the research. Data extraction for this research will include general information of the study that isresearcher’s name/s, study name, publication year and country in which the study was performed. Next, the nature of study population was covered including the age and number of participants. Further, the examination and classification of exposure was done and outcome was obtained. Lastly, it included the measures of the association that are odds ratio and β coefficients and corresponding 95% confidence intervals. Inconsistencies on literature review and data extraction process were settled by consulting the mentor.

The generalized relationship between sleep duration and overweight/obesity will be estimated using the inverse of variance as the weight to calculate the pooled ORs and 95% CIs will compare the least to most category of sleep hours. Standard errors will be sprung from the fully adjusted ORs and 95% CIs in the primary studies.

The heterogeneity among the studies will be assessed through inspection of forest plots and Cochran’s Q test with a P ≤ 0.10 will be regarded as considerable heterogeneity. In addition, the heterogeneity will be measured using the I2 statistic to measure. The low, moderate, and high levels of heterogeneity will beconsidered as <30%, 30–50%, and >50%, respectively.The effects of Small-study and publication bias will beevaluated by funnel plot asymmetry and subsequently by Egger’s regression asymmetry test. Where needed, the publication bias will be adjusted using the Duval and Tweedie nonparametric “trim and fill” method.Robustness of the findings was evaluated through sensitivity analysis..All analysis will be done using STATA statistical software.

Week 1	Conduction of initial research for proposal formulation and submission
Week 2	Submission of proposal and starting the research
Week 3-4	Reviewing of the relevant literature and conducting secondary research
Week 5	Summarising the findings of the secondary research
Week 6	Drafting the research from the outcomes achieved
Week 7	Consulting the mentor
Week 8	Finalising the research by incorporating the feedback
Week 9	Submitting the completed and finalised research

It is established through the findings of several researches that childhood obesity is an independent underlying cause of chronic diseases subsequently. Therefore, identification of the modifiable risk factors of obesity/overweight in Australian childhood will be of great public health implication especially to close the health outcome and life expectancy gap between indigenous and non-indigenous children. This will help Australia in eliminating the risk of development of obese or overweight children which in turn transform into obese or overweight adults.

Approach and Methodology

In this context, findings from prospective cohort studies were inconsistent. One systematic review which evaluated the longitudinal studies in children and adolescents revealed that most of the researches indicated an inverse relationship between sleep duration and overweight/obesity (Connelly, et al., 2007). However, the review did not quantitatively evaluated the overall association. So, this research will assess the relationship between sleep duration and the risk of childhood obesity as well as the associated anthropometric factors by quantitatively reviewing data from the studies.

In addition, until now there is a lack of good understanding about the mechanisms of sleep-weight association. Since there is little knowledge of mechanisms involved, required measures can’t be taken to eradicate this trend by removing the underlying cause. This research also aims to identify the probable mechanisms between thisassociation do that it can open gates for further research in future which will assist in development of relevant public health interventions. This research will also specify the negative metabolic effects of insufficient sleep and will open ground for research with preventive approach.

The overall estimated budget of the research is estimated to be $650. Specific requirements for the conduction of research amounting to this sum is mentioned below.

1. Costs of staffing and overhead-Several staff including review group associates, information official, administrative, statistician, and data input as suitable for the review duration. Overheads related to services given by organization such as communications network, space, central administration.
2. Database accessibility and acquisition of articles to include all the relevant articles.
3. Cost of retrieving databases- some of the databases are free but some include charges for accessibility. Cost will be incurred upon retrieving the full-text articles selected for the review. Since only English literature articles were included no translation cost was required.
4. Communication costs- this includes costs of meetings, teleconferences and mailing costs, etc. to the different members of the research team.
5. Equipment- Computers and software, printing and photocopying, and office supplies.
6. Group training costs- Funds for training workshops
7. Conference costs
8. Publication costs

Previous researchers have identified a relationship between lack of sufficient sleep by children and development of obesity or overweight in their later life. Obesity has been established as one of the major underlying cause of several metabolic chronic disorders such as cardiovascular impairment, diabetes, etc. A gap exists between the health outcomes and life expectancy of native and non-native Australian children. This gap can be closed by reducing the prevalence of childhood obesity among Australian children. To reduce childhood obesity, the modifiable risk factor such lack of sufficient sleep can be removed. It can be achieved by identifying the mechanisms involved in the relationship between lesser sleep duration and increased risk of obesity. This research aims to verify the relationship along with identification of the possible mechanisms responsible for the relationship. A systematic review will be conducted in which all the relevant research articles published between the years of 2008 and 2018 will be included. The abstracts of all the articles published in English pertaining to sleep-weight association will be screened to be included in the final review. A total time of 9 weeks is expected to be taken from preparing the proposal to submitting the final draft of the conducted research.

References

Australian Sleep Health Foundation, 2011. Sleep needs across a lifespan 2011. [Online]
Available at: https://www.sleephealthfoundation.org.au/fact-sheets-a-z/230-sleep-needs-across-the-lifespan.html
[Accessed 25 October 2018].

Boodai, S., Cherry, L., Sattar, N. & Reilly, J., 2014. Prevalence of cardiometabolic risk factors and metabolic syndrome in obese Kuwaiti adolescents. Diabetes Metab Syndr Obes, Volume 7, pp. 505-511.

Connelly, J., Duaso, M. & Butler, G., 2007. A systematic review of controlled trials of interventions to prevent childhood obesity and overweight: a realistic synthesis of the evidence. Public Health, 121(7), pp. 510-7.

Dollman, J., Ridley, K., Olds, T. & Lowe, E., 2007. Trends in the duration of school-day sleep among 10- to 15-year-old South Australians between 1985 and 2004. Acta Paediatrica, 96(7), p. 1011–4.

Han, J., Lawlor, D. & Kimm, Y., 2010. Childhood obesity. The Lancet, 375(9727), p. 1737–48.

Jarrin, D., McGrath, J. & Drake, C., 2013. Beyond sleep duration: distinct sleep dimensions are associated with obesity in children and adolescents.. Int J Obes, 37(4), p. 552–8.

Matricciani, L., Olds, T. & Petkov, J., 2012. Secular trends in the sleep time of school-aged children and adolescents. Sleep Medicine Reviews, 16(3), pp. 203-11.

Patel, S. R. & Hu, F. B., 2008. Short sleep duration and weight gain: a systematic review. Obesity (Silver Spring), 16(3), pp. 643-653.