Author: Dr Rachael Wood, Consultant in Public Health Medicine, NHS National Services Scotland, Information Services Division
The 14th to 20th January 2019 is National Obesity Awareness Week - a good time to reflect on child overweight and obesity.
Levels of childhood overweight and obesity in Scotland
There are several sources of information on childhood overweight and obesity levels in Scotland. Figures based on all children in the first year of primary school are published by the NHS National Services Scotland, Information Services Division (ISD) every December. Annual estimates for children aged two to fifteen years are available from the Scottish Health Survey. The Growing Up in Scotland study provides occasional in depth reports on children’s growth.
The latest figures from ISD show that in school year 2017/18, of more than 50,000 children in the first year of primary school (Primary 1, aged 4½ to 6 years) measured across Scotland, 12% of children were at risk of overweight and a further 10% were at risk of obesity (based on the ‘UK90’ reference and using the epidemiological thresholds).
If children’s BMI levels were the same now as in the 1980s, we would expect around 10% of children to be at risk of overweight and around a further 5% to be at risk of obesity. It is clear therefore that children’s BMI has shifted upwards over time, with considerably more children now falling into the high BMI categories.
The overall percentage of children at risk of overweight or obesity has shown little change since reliable figures became available (initially for some areas of Scotland only) in school year 2001/02. This indicates that the most rapid rise in child unhealthy weight levels happened before this time. Other information sources suggest that the increase in children’s BMI was most marked over the 1970s to mid 1990s.
Inequalities in child overweight and obesity
The ISD figures show that in 2017/18, Primary 1 children living in more deprived areas (as defined by quintiles of the Scottish Index of Multiple Deprivation) were somewhat more likely to be at risk of overweight and much more likely to be at risk of obesity than children living in the least deprived areas.
Source: NHS National Services Scotland, Information Services Division
Inequalities in overweight and obesity among Primary 1 children have increased over time. In 2001/02, the proportion of Primary 1 children at risk of overweight or obesity was similar for all deprivation categories. Since then, the proportion of children at risk of overweight or obesity has increased in the most deprived areas but decreased in the least deprived areas, resulting in the current high levels of inequality. Examining the different categories of overweight and obesity separately shows that the increase in inequality over time has been most marked for the most extreme levels of high BMI: very high BMI in early childhood is increasingly a problem concentrated in Scotland’s most deprived areas.
Source: NHS National Services Scoltand, Information Services Division
What happens after Primary 1?
A recent report from the Growing Up in Scotland study examined the BMI of around 2,700 children born in 2004/05 who were measured at age six and again at age ten years (UK90 reference, epidemiological thresholds). The findings show that children’s BMI centile tends to increase as they progress through primary school. Two out of three children who were at risk of overweight at age six remained at risk of overweight or obesity by age ten. More than nine out of ten children who were at risk of obesity at age six remained at risk of overweight or obesity by age ten.
Growing Up in Scotland also showed that the inequalities that are evident by Primary 1 widen as children progress through primary school: the upward shift in BMI centile between age six and age ten is more pronounced for children from disadvantaged backgrounds.
What is causing child overweight and obesity, and what can be done about it?
The epidemic of child (and adult) overweight and obesity that unfolded over the 1970s to mid 1990s reflects fundamental social and economic shifts. The increasing commodification and commercialisation of food, reflected in increasing promotion and affordability of energy dense food and drinks, and an increasing proportion of calorie intake coming from food and drink prepared/consumed outwith the home, has been of fundamental importance. Increases in sedentary work and leisure time have also contributed.
The immediate and long term negative consequences of childhood overweight and obesity for population health, economic wellbeing, and social equity are well understood. Promotion of healthy weight is included in Scotland’s National Performance Framework and the national Public Health Priorities. Scotland’s Diet and Healthy Weight Delivery Plan, published in July 2018, sets out a policy commitment to halve child obesity levels in Scotland by 2030 and significantly reduce inequalities in overweight and obesity.
The key debate now focuses on the action required to deliver these ambitions, and whether the level of change needed will prove feasible in the face of multiple vested interests, in particular within the food industry. Overweight and obesity are intergenerational problems, with maternal obesity being one of the strongest risk factors for child obesity. A holistic, life-course approach to the promotion of healthy weight will therefore be required.
Finally, the public health community needs to face the fact that whilst efforts to promote healthy weight have shown some success among families from advantaged areas, to date they have utterly failed families living in deprived areas of Scotland. Levels of overweight, and in particular obesity, continue to increase among children from deprived areas, reflecting the high structural barriers to maintaining a healthy weight experienced in these communities. There is an urgent need for us to collectively do better to ensure that Scottish children from disadvantaged areas have the same chance of maintaining a healthy weight as children from our most advantaged areas.