Global Health Observatory (GHO) data

Information on estimation methods

The mortality and risk factor data presented here were estimated using standard methods to maximize cross-country comparability. They are not necessarily the official statistics of Member States.

Mortality

Age- and sex-specific all-cause mortality rates were estimated for 2000-2012 from revised life tables, published in World Health Statistics 2014 (1). Total number of deaths by age and sex were estimated for each country by applying these death rates to the estimated resident populations prepared by the United Nations Population Division in its 2012 revision (2).

Causes of death were estimated for 2000-2012 using data sources and methods that were specific for each cause of death (3). Vital registration systems which record deaths with sufficient completeness and quality of cause of death information were used as the preferred data source. Mortality by cause was estimated for all Member States with a population greater than 250,000. These NCD mortality estimates are based on a combination of country life tables, cause of death models, regional cause of death patterns, and WHO and UNAIDS programme estimates for some major causes of death (not including NCDs). Detailed information on methods for mortality and causes of death estimates were published previously (3).

Age-standardized death rates for cardiovascular diseases, cancers, chronic respiratory diseases, and diabetes were calculated using the WHO standard population (4). Proportional mortality (% of total deaths, all ages, and of both sexes) for communicable, maternal, perinatal and nutritional conditions; injuries; cardiovascular disease; cancer; chronic respiratory disease; diabetes; and other NCDs is reported for 2012 (5).

The 2012 probability of dying between ages 30 and 70 years from the four main NCDs was estimated using age-specific death rates (in 5-year age groups, e.g. 30-34… 65-69, for those between 30 and 70) of the combined four main NCD categories, for each Member State (5). Using the life table method, the risk of death between the exact ages of 30 and 70, from any of the four causes and in the absence of other causes of death, was calculated using the equation below. ‪The ICD codes used are: Cardiovascular disease: I00-I99, ‪Cancer: C00-C97, ‪Diabetes: E10-E14, ‪and Chronic respiratory disease: J30-J98.‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬ Further details on methods of calculation are published elsewhere (6).‬‬‬‬

Metabolic/biological risk factors *

Estimates for metabolic/biological risk factors (BMI, overweight and obesity, diabetes and blood pressure) are based on aggregated data provided to WHO and the NCD Risk Factor Collaboration (NCD-RisC) and obtained through a review of published and unpublished literature. The inclusion criteria for estimation analysis included data that had come from a random sample of the general population, with clearly indicated survey methods (including sample sizes) and risk factor definitions. Adjustments were made for the following factors so that the same indicator could be reported for common years in all countries: standard risk factor definition, standard set of age groups for reporting; standard reporting year, and representativeness of population. To further enable comparison among countries, age-standardized estimates were calculated. This was done by adjusting the crude estimates to the WHO Standard Population (4). This adjusts for the differences in age/sex structure between countries. Uncertainty in estimates takes into account sampling error and uncertainty due to statistical modeling. Further detailed information on the methods and data sources used to produce these estimates are available elsewhere (7,8,9).

* Data shown for cholesterol are former estimates for 2008 ; updated cholesterol estimates will be available in due course.

Insufficient Physical Activity – Adults

For comparable estimates of insufficient physical activity for adults, surveys were included that presented sex- and age-specific prevalence with sample sizes (minimum: n=50), using the definition of not meeting the WHO recommendations on physical activity for health (10), or a similar specific definition. Only surveys were included that captured activity across all domains of life including work/household, transport and leisure time. Data had to come from a random sample of the general population, with clearly indicated survey methods.

In order to report comparable data for a standard year (2010) and standard age groups, adjustments were made for definition of insufficient physical activity, over-reporting of the International Physical Activity Questionnaire (IPAQ) (11-13), coverage (urban and rural), and age coverage of the survey. Using regression modelling techniques, crude adjusted prevalence values were produced for 5-year age groups, and then combined for ages 18+ years, using country population estimates. To further enable comparison among countries, age-standardized comparable estimates were produced. This was done by adjusting the crude estimates to an artificial population structure, the WHO Standard Population (4), that closely reflects the age and sex structure of most low and middle income countries. This corrects for the differences in age/sex structure between countries. Uncertainty in estimates was analysed by taking into account sampling error and uncertainty due to statistical modelling.

Insufficient Physical Activity – School-going adolescents

For comparable estimates of insufficient physical activity for school going adolescents, surveys were included that presented sex- and age-specific prevalence with sample sizes (minimum: n=50), using the definition of not meeting the WHO recommendations on physical activity for health (10), or a similar definition (less than 60 minutes of activity on less than 5 days per week) . Data had to come from a random sample of the adolescent population, with clearly indicated survey methods.

In order to report comparable data for a standard year (2010) and standard age groups, adjustments were made for definition of insufficient physical activity, and coverage. Using regression modelling techniques, crude adjusted prevalence values were produced for the ages 11-17 years.

References
  • World Health Organization. World Health Statistics 2014. Geneva: WHO; 2014.
  • United Nations Population Division. World population prospects - the 2012 revision. 2013. New York, United Nations.
  • WHO methods and data sources for country‐level causes of death 2000‐2012. World Health Organization, Geneva 2014.
  • Ahmad OB et al. Age Standardization of Rates: A New WHO Standard (Technical Report). GPE Discussion Paper Series: No.31. Geneva, World Health Organization, 2001.
  • WHO. Global Health Estimates: Deaths by Cause, Age, Sex and Country, 2000-2012. Geneva, World Health Organization, 2014.
  • WHO. Noncommunicable Diseases Global Monitoring Framework: Indicator Definitions and Specifications. Geneva, World Health Organization, 2014.
  • NCD Risk Factor Collaboration (NCD-RisC). Worldwide trends in diabetes since 1980: a pooled analysis of 751 population-based studies with 4.4 million participants. Lancet 2016, 387:1513-1530.
  • NCD Risk Factor Collaboration (NCD-RisC). Trends in adult body-mass index in 200 countries from 1975 to 2014: a pooled analysis of 1698 population-based measurement studies with 19.2 million participants. Lancet 2016, 387:1377-1396.
  • NCD Risk Factor Collaboration (NCD-RisC). Worldwide trends in blood pressure from 1975 to 2015: a pooled analysis of 1479 population-based measurement studies with 19.1 million participants. Lancet 2017, 389:37-55.
  • WHO. Global recommendations on physical activity for health. Geneva, Switzerland: World Health Organization 2010.
  • Ainsworth BE, Macera CA, Jones DA, et al. Comparison of the 2001 BRFSS and the IPAQ physical activity questionnaires. Medicine and Science in Sports and Exercise, 2006, 38:1584-92.
  • Ekelund U, Sepp H, Barge S, et al. Criterion-related validity of the last 7-day, short form of the International Physical Activity questionnaire in Swedish adults.Public Health Nutrition, 2006, 9:258-65.
  • Rzewnicki R, Vanden Auweele Y, de Bourdeaudhuij I. Addressing overreporting on the International Physical Activity Questionnaire (IPAQ) telephone survey with a population sample. Public Health Nutrition, 2003, 6:299-305.