A third of the world’s population, about 2.3 billion people, is experiencing over five ailments, according to a new analysis from the Global Burden of Disease Study (GBD) 2013. Findings from this study are published in The Lancet.

An analysis of 35,620 sources of information on disease and injury from 188 countries between 1990–2013 was conducted. The team set out to determine the extent of disabling disorders and the overall burden on health systems from 301 acute/chronic diseases and injuries, as well as the 2,337 health sequelae that result from one or more of these disorders.

Across the world, the proportion of lost years of healthy life (disability-adjusted life years [DALYS]) due to illness rose from one-fifth (21%) in 1990 to almost one-third (31%) in 2013. Moreover, only 4.3% of the world’s population had no health problems in 2013, researchers reported.

The leading causes of health loss have barely changed over the years as low back pain, depression, iron-deficiency anemia, neck pain, and age-related hearing loss result in the largest overall health loss worldwide in 1990 and 2013, as measured by Years Lived with Disability (YLD). Researchers noted that disability rates were declining much more slowly than death rates. Rates of diabetes have been significant over the past 23 years with a 43% rise, whereas death rates from diabetes have increased by only 9%.

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Other key findings include:

  • In 2013, low back pain and major depression ranked among the top ten greatest contributors to disability in every country, causing more health loss than diabetes, chronic obstructive pulmonary disease, and asthma combined.
  • Worldwide, the number of individuals with several illnesses rapidly increased both with age and in absolute terms between 1990 and 2013. In 2013, about a third of children aged 0–4 years in developed countries had no disorder compared with just 0.03% of adults older than 80 years. Furthermore, the number of individuals with more than ten disorders increased by 52% between 1990 and 2013.
  • Eight causes of chronic disorders – mostly non-communicable diseases – affected more than 10% of the world population in 2013: cavities in permanent teeth (2.4 billion), tension-type headaches (1.6 billion), iron-deficiency anemia (1.2 billion), glucose-6-phosphate dehydrogenase deficiency trait (1.18 billion), age-related hearing loss (1.23 billion), genital herpes (1.12 billion), migraine (850 million), and ascariasis (800 million; giant intestinal roundworm).
  • The number of years lived with disability increased over the last 23 years due to population growth and ageing (537.6 million to 764.8 million), while the rate (age-standardized per 1000 population) barely declined between 1990–2013 (115 per 1000 people to 110 per 1000 people).
  • The main drivers of increases in the number of years lived with disability were musculoskeletal, mental, and substance abuse disorders, neurological disorders, and chronic respiratory conditions. HIV/AIDS was a key driver of rising numbers of years lived with disability in sub-Saharan Africa.
  • There has also been a startling increase in the health loss associated with diabetes (increase of 136%), Alzheimer’s disease (92% increase), medication overuse headache (120% increase), and osteoarthritis (75% increase).
  • In central Europe, falls cause a disproportionate amount of disability and health burden, ranking as the second leading cause of disability in 11 of 13 countries. In many Caribbean nations anxiety disorders ranked more highly, and diabetes was the third greatest contributor to disability in Mexico, Nicaragua, Panama, and Venezuela. Disability from past war and conflict was the leading contributor to health loss in Cambodia, Nicaragua, Rwanda, and ranked second in Vietnam.

For more information visit TheLancet.com.