Regional differences in Childhood BMI data - The Malta Childhood National Body Mass Index Study

Introduction

The world has seen the prevalence of obesity increasing year on year reaching epidemic levels in many countries..¹ For this reason, Public Health entities have put obesity on the forefront of their agenda. Particular focus is being given to childhood obesity. It is well known that overweight children become overweight adults and therefore tackling the problem from an early stage may be helpful in reducing the prevalence of obesity and its detrimental effects on health²

Malta is no stranger to this phenomenon. Several studies have repeatedly demonstrated a high prevalence of overweight and obesity in childhood, confirming a worsening picture despite the implementation of various policies and guidelines to attempt to contain and possibly reverse these trends.^3-5

In 2015, a national study was carried out to measure the body mass index (BMI) of all children attending school in Malta thereby covering ages 5 to 15. This study was unique since all children were included for measurement rather than just a sample.⁶

Schools in Malta are run by three main groups: 1) State schools are free and government-led; 2) Church schools are partly subsidized and run by the Roman Catholic Church; and 3) Independent schools are a mixture of schools privately run by different organisations against a set fee. Primary schools usually cater for children from 5 till 10 and secondary schools cater for students from 11 to 16 years approximately.

Part of the data collected from the Malta Childhood National BMI study (2015-16) included the locality of residence of the child.⁶ The purpose of this study was to describe the geographical distribution of prevalence of childhood overweight and obesity in Malta.

Method

Ethics

Ethical approval for the Malta National Childhood BMI study was obtained from the Ethics Committee of the Malta Education Division and the Malta University Research Ethics Committee. The Malta National Commissioner for Data Protection also endorsed this project. Permissions were also obtained separately from the Central Church schools authorities and from the Independent schools.

Data Collection

Data was collected using identical scale-stadiometers (GIMA 27288 PEGASO DIGITAL SCALE) in all schools. Measurements were carried out by the Physical Education teachers in each respective school or college. Each child was measured once. Teachers were shown how to measure height accurately and a reminder handout was attached to each weighing scale. Teachers were also responsible for data inputting into a standardised and bespoke spreadsheet.⁷ Physiotherapists coordinated by the Malta Association of Physiotherapists and other administrative staff also helped with data collection.

Current World Health Organisation (WHO) BMI cut-offs were used. Key values were overweight (between WHO 85-95 percentiles), obese (greater than WHO 95th percentile), and underweight (less than the 5th percentile).⁸

Students’ BMI data was grouped according to geographical locality and region of birth. The Maltese islands are divided into six regions by Malta’s National Statistics Office: North, Northern Harbour, Southern Harbour, South East, West, and Gozo & Comino.

Results

This study included 145 schools – 39 Church, 94 State and 12 Independent schools, some of which have primary and/or secondary components, and some of which are coeducational and while others are not. Data was available for 41343 students – 21147 males and 20196 females – ranging in age from 4.7-17years.

Summary statistics and number of children overweight, obese and underweight, by gender for primary and secondary schools by region, are shown in Table 1. Table 2 displays percentages for the same data for overweight, obese and underweight. Figures 1 and 2 display ranked body mass index mean (and 95% confidence intervals) by region for primary and secondary schools respectively.

Figure 1

Ranked body mass index mean (and 95% confidence intervals) by region for primary school males and females

Figure 2

Ranked body mass index mean (and 95% confidence intervals) by region for secondary school males and females

After ranking, chi test for trend for overweight and obesity by region showed highly significant trends for male primary (chi for trend=38.7, p<0.0001), male secondary (chi for trend=11.0, p=0.0009), females primary (chi for trend=30.6, p<0.0001) and females secondary schools (chi for trend=30.6, p<0.0001). 

Discussion

This analysis shows significant differences in BMI between children living in the Northern and those living in the Southern parts of the island, despite the small size of the country at just 316km.² This disparity has been shown in previous studies but a study in 2011 seemed to suggest that this trend was fading.⁹ However, the trend is clearly still significantly present. Data from the Maltese National Statistics Office provide a picture of a wealthier North when compared to a less prosperous South.^10-11 For example, on average, persons living in the North were also found to live in larger residences, have better literacy levels, have a higher chance of owning their home (rather than renting) and have lower levels of unemployment when compared to the South^10-11

These trends demonstrate a relationship between socioeconomic status and obesity, reinforcing studies done in other countries. For example, American datasets over the years have shown that higher levels of childhood overweight and obesity were present in families with parents having a lower level of education, those living below the poverty level and those living in low-income neighbourhoods.¹² However, this is overlaid by increasing trends in obesity rates in children of parents of all income levels and educational levels.¹³

The main strengths of this study are derived from the inclusion of the entire childhood school-age cohort. This provided the researchers with a detailed picture of the real situation regarding the obesity epidemic in Malta and will assist the local authorities when channelling limited resources into the right areas. These results show that the South East and Southern Harbour areas need the highest focus of attention. Other strengths are that results reported were measured directly, not self-reported as in several other studies. Using the same instruments helped reduce inter-observer bias. A regular mechanism of checking and recalibration of scales was done before and after the end of each study period. Training teachers also helped reduce bias using measurement techniques that were part of standard operating procedures developed for the purpose of the pilot European Health Examination Survey.¹⁴ Due to the large number of students involved, data collection was limited to a number of key factors. In fact, ethnicity was not included as a variable in the data collection sheet. Differences in the ethnic mix between the regions and differences in BMI between different ethnicities were not assessed in this study.

Obesity is an important health determinant. Despite the North-South differences, all regions show a high prevalence of overweight and obesity. Following these results, further research into socioeconomic determinants of local overweight and obesity should be embarked upon as these may yield insights into how best to target the problem from both the prevention and intervention aspects. The authors of this study call on Government to provide the necessary leadership to tackle this major issue for our islands. Although there are regional differences, obesity must be tackled as a national health emergency so that all possible resources are channelled towards reducing the high obesity rates noted from early childhood to adulthood in our Maltese population. Making healthy food more accessible through incentives, possibly through taxation of the unhealthy options, should also be considered. A regular repetition of this study would also be beneficial to determine trends of childhood overweight and obesity in Malta and monitor the effect of any prevention and intervention programmes being implemented.

References

1. World Health Organization. Action Plan for Implementation of the European Strategy for the Prevention and Control of Noncommunicable Diseases 2012 – 2016. WHO Regional Office for Europe, 2012.
2. Lakshman R, Elks CE, Ong KK. Childhood Obesity. Circulation. 2012;126(14):1770-1779.
3. Superintendence of Public Health. A Healthy Weight for Life: A National Strategy for Malta. Superintendence of Public Health, 2012.
4. Health Promotion and Disease Prevention Directorate. Food and Nutrition Policy and Action Plan for Malta 2015-2020. Parliamentary Secretary for Health, 2014.
5. Ministry for Education and Employment. A Whole school approach to a healthy lifestyle: healthy eating and physical activity policy. Ministry for Education and Employment, 2015.
6. Grech V, Aquilina S, Camilleri E, Spiteri K, Busuttil ML, Farrugia Sant’Angelo V et al. The Malta Childhood National Body Mass Index Study - A  Population Study. J Pediatr Gastrolenterol Nutr 2016 Oct 4. (in press)
7. Grech V, Aquilina S, Camilleri E. Depicting the analyses of the first National Maltese Childhood BMI study. Images Paediatr Cardiol 2015;17:4-13.
8. World Health Organisation. Growth reference 5-19 years; BMI-for-age (5-19 years). Available from: http://www.who.int/growthref/who2007_bmi_for_age/en/
9. Farrugia Sant’Angelo V, Grech V. Comparison of body mass index of a national cohort of Maltese children over a 3-year interval. Maltese Med J 2011;23:34-39.
10. National Statistics Office. Social Security Benefits: A Locality Perspective – 2009. Malta: National Statistics Office, 2009.
11. National Statistics Office. Census of population and housing 2011. Malta: National Statistics Office, 2011.
12. Singh GK, Kogan MD. Childhood obesity in the United States, 1976-2008: Trends and Current Racial/Ethnic, Socioeconomic, and Geographic Disparities. A 75th Anniversary Publication. Health Resources and Services Administration, Maternal and Child Health Bureau. Rockville, Maryland: U.S. Department of Health and Human Services, 2010.
13. Ogden CL, Lamb MM, Carroll MD, Flegal, KM. Obesity and socioeconomic status in children: United States 1988–1994 and 2005–2008. NCHS data brief no 51. Hyattsville, MD: National Center for Health Statistics, 2010.
14. Kuulasmaa K, Tolonen H, Koponen P, Kilpeläinen K, Avdicová M, Broda G et al. An overview of the European Health Examination Survey Pilot Joint Action. Arch Public Health. 2012;70:20.

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