Attributable burden: The disease burden attributed to a particular risk factor. It is the reduction in fatal and non-fatal burden that would have occurred if exposure to the risk factor had been avoided (or was reduced to its theoretical minimum).
Body mass index: An internationally recognised standard for classifying overweight and obesity in adults, calculated by dividing a person’s weight in kilograms by the square of their height in metres.
Burden of disease (and injury): The quantified impact of a disease or injury on a population using the disability-adjusted life years (DALY) measure.
COVID-19 (Coronavirus disease 2019): An infectious disease caused by the SARS-CoV-2 virus.
Disability-adjusted life years (DALY): A year of healthy life lost, either through premature death or living with disability due to illness or injury.
Disease: A broad term that can be applied to any health problem, including symptoms, diseases, injuries and certain risk factors, such as high blood cholesterol and obesity. Often used synonymously with condition, disorder or problem.
Fatal burden: The burden from dying prematurely as measured by years of life lost (YLL). Often used synonymously with years of life lost, and also referred to as ‘life lost’. See ‘Years of life lost’.
Metabolic equivalent of tasks (METs): A measure of physical activity representing the rate of energy expenditure incorporating the duration and intensity of activity, with one MET equivalent to 1 kcal/kg/hr, which is about the energy expended in sitting, with 1 MET-minute equal to 1 minute of activity at an intensity of 1 kcal/kg/hr.
Non-fatal burden: The burden from living with ill health as measured by years lived with disability (YLD). Often used synonymously with years lived with disability, and also referred to as ‘health loss’. See ‘Years lived with disability’.
Obesity: Category used to describe the amount of body mass a person has above what is considered ideal. Defined as a body mass index equal to or greater than 30 kg/m2. See ‘Body mass index’.
Overweight: Category used to describe the amount of body mass a person has above what is considered ideal. Defined as a body mass index equal to or greater than 25 kg/m2, but less than 30 kg/m2. See ‘Body mass index’.
Prevalence: Refers to the existence of a disease or event in a population, whether or not it is newly occurring; the prevalence rate is the number of cases existing at a point in time (point prevalence) or over a specified time period (period prevalence) divided by the number of people in the population.
Rate: A burden (YLD, YLL or DALY) rate is one number (the numerator) divided by another number (the denominator). The numerator is commonly the number of years of healthy life lost in a specified time. The denominator is the population at risk of the event. Rates (crude, age-specific and age-standardised) are generally multiplied by a number such as 1,000 to create whole numbers.
Risk factor: Any factor that represents a greater risk of a health condition or health event. For example, smoking, alcohol use, high body mass.
Total (or overall) burden: The sum of fatal burden (YLL) and non-fatal burden (YLD), which totals disability-adjusted life years (DALY). See ‘Burden of disease (and injury)’. See ‘Disability-adjusted life years’.
Years lived with disability (YLD): Measures the years of what could have been a healthy life that were instead spent in states of less than full health. YLD represent non-fatal burden.
Years of life lost (YLL): Measures years of life lost due to premature death, defined as dying before the global ideal life span at the age of death. YLL represent fatal burden.