International Comparisons of Obesity Prevalence

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Adult Data

The following chart uses Organisation for Economic Cooperation and Development (OECD) data. Data from the Health Survey for England for 2009, Welsh Health Survey for 2009, and Scottish Health Survey for 2008; Survey of Lifestyle, Attitudes and Nutrition, Republic of Ireland for 2007 and Northern Ireland Health and Social Wellbeing Survey for 2005/06 are also included.

What are the issues around comparing obesity prevalence internationally?

Some countries publish obesity prevalence based on measured height and weight, whereas others rely on self reported measures to produce obesity prevalence figures. It is likely that obesity prevalence estimates based on self-reported measures are lower than those based on actual measurements. This difference limits comparison between studies. Obesity prevalence data from only 14 of the 33 countries presented in the chart are based on measured weight and height. The data here show that countries with measured height and weight data have a high prevalence of obesity (with the exception of Japan which has a low prevalence). This chart uses the latest available data. Although most of the prevalence estimates here are for 2008 it is important to note that there are differences in the years for the prevalence estimates. Where possible prevalence estimates for the same time period should be compared. Trend data are useful for comparing obesity prevalence over time. Some trend data can be seen in the Adult data download at the top of this page. Most of the data here are obtained from national health surveys which are likely to be representative of the general population. Only single year estimates for each country are presented. These data are not age or sex standardised so differences in the age and sex structure of the populations have not been accounted for.

How does the prevalence of obesity in England compare with other countries and in particular within Britain and Ireland?

The prevalence of obesity in England is estimated using measured weight and height. The 2009 estimate is 23.0% and is high compared to most other countries, with Japan and South Korea having the lowest estimates of obesity prevalence. Estimates for Scotland and Ireland are also based on measured weight and height, but the estimate for Wales is based on self reported height and weight and is therefore likely to be an underestimate. Scotland and Ireland appear to have higher obesity prevalence compared to England but as no measures of uncertainty are provided for these estimates we cannot be certain this is a real difference. The figures for Northern Ireland date from 2005 as no more recent data were available.

Adult obesity prevalence, latest available data*

Metadata for OECD Health Data 2008 can be found at: www.ecosante.org/oecd.htm

Source:

For more information on international trends click here

Child Obesity

The relationship between body mass index and fatness in children varies substantially with age, so a growth reference is used to define overweight and obesity in different age groups. The British 1990 growth reference (UK90) is the most commonly used reference within the UK, and the International Obesity Task Force (IOTF) thresholds, World Health Organization Growth Reference and the Center for Disease Control Growth Reference are more frequently used in other countries.

All estimates in the table below are based on measured height and weight and use the 85th and 95th centiles of the UK90 reference to define overweight and obese for population monitoring purposes. Northern Ireland appears to have the highest prevalence of childhood obesity, followed by Wales and England. The lowest prevalence is observed for Ireland, although the data are for 2002 and it is likely that more recent data would show a higher prevalence. Using the UK90 reference, overweight and obesity prevalence are higher among boys than girls.

Percentage of children obese and overweight (including obese) in the UK and Ireland

International data on the prevalence of overweight and obesity are available from the International Association for the Study of Obesity and are presented in the following chart. These estimates are based on measured height and weight and all except Austria and Belgium use the IOTF thresholds to classify individuals as overweight or obese.

The United States appears to have the highest prevalence of childhood overweight and obesity. Scotland, England, Northern Ireland and Ireland all appear to have high prevalence of childhood overweight and obesity. However as is clearly demonstrated in the chart, data are collected over different time periods for different age groups and in some cases different thresholds have been used.

Prevalence of overweight and obesity varies by age, so different age groupings will also have an impact on the figures. Non-participation may also result in biased estimates. Overweight or obese children may be less likely to participate in such studies, and as a result the prevalence of overweight and obesity could be underestimated. It is important that these differences and causes of potential variation are taken into account when comparing national figures, and direct comparisons should only be made between countries with comparable sources of data.

Prevalence of overweight (including obese) for boys in selected countries

Based on measured height and weight. Showing measurement year and age group measured

Prevalence of overweight, including obese (%)

Prevalence of overweight (including obese) for girls in selected countries

Based on measured height and weight. Showing measurement year and age group measured

Prevalence of overweight, including obese (%)

  1. All rates use IOTF reference centiles to define overweight and obese except Austria & Belgium which use CDC thresholds.
  2. Only countries with comparable age groups have been included. Countries where only children from a narrow age band have been measured are not shown (e.g. Italy and Finland).

Source: International Association for the Study of Obesity, IASO link: http://www.iaso.org/?map=children Health Survey for England; North South Survey of Children's Height, Weight & Body Mass Index; and Scottish Health Survey.