Technical notes

Summary of change in study population for deaths data

The previous Australia’s Health article on Health of veterans, presented information on the post-2001 ex-serving ADF members cohort based on the current ADF personnel system. Where possible, data have been updated to be based on the post-1985 ex-serving ADF members cohort. The study population does not include ADF members who separated prior to 1 January 1985. Research is constrained by what is technically possible with the systems and information infrastructure in place before 1985.

The AIHW, in collaboration with Defence and DVA, is working to increase the range of data available about veterans through data linkage initiatives and survey opportunities.

Age-standardised rates

Age-standardised rates are rates standardised to a specific standard age structure to facilitate comparison between populations and over time. In this report, they are directly age-standardised rates adjusted using the Australian standard population, that is, the Australian estimated resident population (ERP) as at 30 June 2001.

For some instances when using data from the 2017-18 National Health Survey (NHS) involving small samples sizes, particularly for self-reported DVA clients, the counts did not satisfy the minimum data quality requirements for conducting age-standardisation. In these instances, a general comment about the possible impact of age on the data comparisons being made has been included.

Using survey-based data

Data from the NHS is based on self-reported veteran status, and all numbers are estimates that have been weighted to the Australian population. The sample selection, together with its weighting, is not intended to represent the veteran population, and therefore may over- or under-represent certain types of veterans.

Veterans made up a small portion of the overall NHS sample, which may cause some issues with the reliability and validity of results in this report. The sample of veterans who were also DVA clients was even smaller, so any differences observed between this group and others mentioned in this report should be interpreted with caution and may be due to chance.

Data based on a sample rather than the whole population are subject to a degree of error, termed sampling error. This error describes the difference between the result obtained from the sample and the ‘true’ result for the whole population. The level of uncertainty associated with sampling error can be represented using confidence intervals. In this report, confidence intervals display the range in which there is a 95% chance the true value lies. In relevant bar graphs, the vertical lines at the top of each bar represent the confidence intervals. Narrow confidence intervals indicate high precision in results, and wide confidence intervals indicate lower precision. Sample-based results from a small population group, such as veterans, are more likely to have wide confidence intervals. As a result of sampling error, it is possible that a difference between two sample-based results is due to chance rather than being a true difference.

The ABS survey data presented in this report have been tested for significance at the 5% level using confidence intervals:

  • If the confidence intervals for two results do not overlap, the difference is statistically significant
  • If the confidence intervals for two results do overlap, it is likely but not certain that the difference is not statistically significant. In this case, a confidence interval for the difference is calculated. If the confidence interval for the difference does not include zero (0), the difference is statistically significant.

A significant result means it would occur by chance fewer than 1 in 20 times. Where comparisons are found to be not statistically significant, there may still be a real difference that the statistical test did not detect, but the difference may be of practical importance.

There are a number of methods to test statistical significance, each with varying levels of precision. This method has been used where data were sourced directly from the ABS. The significance of results from other studies or reports has been presented as published by the original authors, though the method used may differ from the method presented here.

Abbreviations
ABS Australian Bureau of Statistics
ADF

Australian Defence Force

BMI Body Mass Index
AIHW

Australian Institute of Health and Welfare

DVA Department of Veterans’ Affairs
ERP Estimated Resident Population
NDI National Death Index
NHMD National Hospital Morbidity Database
NHMRC

National Health and Medical Research Council

NHS National Health Survey
NMD National Mortality Database
PBS Pharmaceutical Benefits Scheme
PMKeyS Personnel Management Key Solution
RPBS Repatriation Pharmaceutical Benefits Scheme (RPBS)
SDAC Survey of Disability, Ageing and Carers
SHSC

Specialist Homelessness Services Collection

age-specific rate: A rate for a specific age group. The numerator and denominator relate to the same age group.

age-standardisation: A way to remove the influence of age when comparing populations with different age structures. This is usually necessary because the rates of many events (e.g. deaths, service use) vary with age. The age structures of the different populations are converted to the same 'standard' structure, and then the disease rates that would have occurred with that structure are calculated and compared.

age structure: The relative number of people in each age group in a population.

alcohol consumption risk guidelines: The NHMRC’s 2009 Australian Guidelines to Reduce Health Risks from Drinking Alcohol were used to assess alcohol consumption.

Lifetime risk: The accumulated risk from drinking either on many drinking occasions, or on a regular (for example, daily) basis over a lifetime. The lifetime risk of harm from alcohol-related disease or injury increases with the amount consumed. For healthy men and women, drinking no more than 2 standard drinks on any day reduces the lifetime risk of harm from alcohol-related disease or injury. In this report, alcohol risk was derived from an individual’s average daily consumption over the 3 most recent days that they had consumed alcohol in the week before the 2017–‍18 NHS interview.

Single occasion risk (alcohol): The risk associated with consumption of alcohol on a single occasion of drinking. on a single occasion of drinking, the risk of alcohol-related injury increases with the amount consumed. For healthy men and women, drinking no more than four standard drinks on a single occasion reduces the risk of alcohol-related injury arising from that occasion. A single occasion of drinking refers to a person consuming a sequence of drinks without their blood alcohol concentration reaching zero in between. To exceed the single occasion risk guidelines, respondents would have consumed more than 4 standard drinks at least once in the past year, prior to the 2017–‍18 NHS interview.

Australia’s Physical Activity and Sedentary Behaviour Guidelines: The guidelines recommend that adult Australians aged 18–64:

  • be active on most, preferably all, days every week
  • accumulate 150 to 300 minutes of moderate intensity physical activity or 75 to 150 minutes of vigorous intensity physical activity, or an equivalent combination of both moderate and vigorous activities, each week
  • do muscle-strengthening activities on at least 2 days each week
  • minimise the amount of time spent in prolonged sitting
  • break up long periods of sitting as often as possible.

For Australians aged 65 and over, the guidelines recommend people should be active every day in as many ways as possible and accumulate at least 30 minutes of moderate intensity physical activity on most, preferably all, days.

Body Mass Index (BMI): The most used method of assessing whether a person is normal weight, underweight, overweight or obese, which is calculated by dividing the person’s weight (in kilograms) by their height (in metres) squared; that is, kg ÷ m2. For both men and women, underweight is a BMI below 18.5, acceptable weight is from 18.5 to less than 25, overweight is from 25 to less than 30, and obese is 30 and over. Sometimes overweight and obese are combined and defined as a BMI of 25 and over. At the time of the 2017–18 NHS interview, respondents had their height and weight measured and subsequently BMI was calculated.

cancer (malignant neoplasm): A large range of diseases where some of the body’s cells become defective, begin to multiply out of control, invade and damage the area around them, and can then spread to other parts of the body to cause further damage.

cardiovascular disease/condition: Any disease of the circulatory system, namely the heart (cardio) or blood vessels (vascular). Includes angina, heart attack, stroke, and peripheral vascular disease. Also known as circulatory disease.

cause(s) of death: All diseases, morbid conditions, or injuries that either resulted in or contributed to death—and the circumstances of the accident or violence that produced any such injuries—that are entered on the Medical Certificate of Cause of Death.

commissioned officer: An appointed Defence member who holds a rank of Midshipman or Officer Cadet, or higher.

condition (health condition): A broad term that can be applied to any health problem, including symptoms, diseases, and various risk factors (such as high blood cholesterol, and obesity). Often used synonymously with disorder.

confidence interval: A range determined by variability in data, within which there is a specified (usually 95%) chance that the true value of a calculated parameter lies.

COVID-19: A disease of the respiratory system, particularly in the early stages of the illness, caused by the coronavirus SARS-CoV-2. Common early symptoms are similar to other respiratory illnesses, but the infection can have a wide variety of manifestations. In some people the infection can progress to become a more severe disease, with the immune system overreacting, resulting in inflammation and lack of oxygen to many parts of the body. This can lead to multiple organ failure and death. Severe symptoms tend to develop in the second week of the disease.

data linkage: The bringing together (linking) of information from two or more different data sources that are believed to relate to the same entity; for example, the same individual or the same institution. This linkage can yield more information about the entity and in certain cases, provide a time sequence—helping to ‘tell a story’, show ‘pathways’ and perhaps unravel cause and effect. The term is used synonymously with ‘record linkage’ and ‘data integration’.

dependant: The partner, parent, step-parent, grandparent, child, step-child, grandchild, sibling or half-sibling of a permanent or former ADF member. The member’s partner’s parent, step-parent, child or step-child may also be included as dependants. Further, a dependant may also include a person who stands in the position of a parent to the member, or a person in respect of whom the member stands in the position of a parent.

disability: An umbrella term for any or all of an impairment of body structure or function, a limitation in activities, or a restriction in participation. Disability is a multidimensional concept and is considered as an interaction between health conditions and personal and environmental factors.

discharge (ADF): Separation from the ADF.

ex-serving ADF members: ADF members in the serving or reserve population on or after 1 January 1985 and who separated after 1 January 1985.

hospitalisation: Synonymous with admission and separation; that is, an episode of hospital care that starts with the formal admission process and ends with the formal separation process. An episode of care can be completed by the patient’s being discharged, being transferred to another hospital or care facility, or dying, or by a portion of a hospital stay starting or ending in a change of type of care (for example, from acute to rehabilitation).

In real terms: Growth in spending, expressed in constant prices, is referred to as ‘real growth’ or ‘growth in real terms’ and represents changes in the real value of the amount of money spent in a given year.

length of service: Length of service describes the time between joining the ADF and separation. Note that the separation point used in this analysis reflects full separation from the ADF – that is, when a member is no longer in permanent or reserve service. For example, a member who transitions from full time service to the inactive reserves is counted as permanent for the purpose of length of service calculations until he or she separates from the reserves.

Medicare: A national, government-funded scheme that subsidises the cost of personal medical services for all Australians and aims to help them afford medical care. The Medicare Benefits Schedule (MBS) is the listing of the Medicare services subsidised by the Australian Government. The schedule is part of the wider Medicare Benefits Scheme (Medicare).

mental illness (or mental disorders): Disturbances of mood or thought that can affect behaviour and distress the person or those around them, so that the person has trouble functioning normally. They include anxiety disorders, depression, and schizophrenia.

mortality: Number or rate of deaths in a population during a given time period.

musculoskeletal condition: One of a group of conditions, along with arthritis and other conditions that affects the bones, muscles, and joints. These other conditions include back pain and problems, juvenile arthritis, osteoarthritis, osteopenia, osteoporosis (low bone density) and rheumatoid arthritis.

outcome (health outcome): A health-related change due to a preventive or clinical intervention or service. (The intervention may be single or multiple, and the outcome may relate to a person, group or population, or be partly or wholly due to the intervention.)

Patient days: The total number of days for all patients who were admitted for an episode of care and who separated during a specified reference period. A patient who is admitted and separated on the same day is allocated 1 patient day.

permanent ADF members: A term that describes ADF members serving in a regular capacity in the Navy, Army or Air Force on continuous full-time service, or participating in the gap year program.

Pharmaceutical Benefits Scheme (PBS): A national, government-funded scheme that subsidises the cost of a wide range of pharmaceutical drugs for all Australians to help them afford standard medications. The Schedule of Pharmaceutical Benefits (schedule) lists all the medicinal products available under the PBS and explains the uses for which they can be subsidised.

prevalence:  The number or proportion (of cases, instances, and so forth) in a population at a given time. In relation to cancer, refers to the number of people alive who had been diagnosed with cancer in a prescribed period (usually 1, 5, 10 or 26 years).

psychological distress: Unpleasant feelings or emotions that affect a person’s level of functioning and interfere with the activities of daily living. This distress can result in having negative views of the environment, others and oneself, and manifest as symptoms of mental illness, including anxiety and depression.

rank: Rank describes organisational and workforce structures that determine a member’s position, conditions, opportunities, and entitlements (such as pay and conditions). The analysis here is based on rank at time of separation. It is presented in two broad groups: commissioned officers and all ranks other than commissioned officer.

rate: One number (the numerator) divided by another number (the denominator). The numerator is commonly the number of events in a specified time. The denominator is the population “at risk” of the event. Rates (crude rates, age-specific rates and age-standardised – see age-standardisation) are generally multiplied by a number such as 100,000 to create whole numbers.

reason for separation: The reasons that ADF members separate from the ADF can be categorised into three broad groups:

  • voluntary separation
  • other involuntary separation
  • involuntary medical separation.

The separation point used in this analysis reflects full separation from the ADF, that is, when a member is no longer permanent or reserve. Separation reason is therefore the reason recorded for leaving the last engagement with the ADF.

Repatriation Pharmaceutical Benefits Scheme (RPBS):  The RPBS is subsidised by the Department of Veterans’ Affairs (DVA), and can be accessed by veterans who have the following DVA cards:

  • Gold or Orange Card (all medical conditions)
  • White Card (specific medical conditions).
  • Under the RPBS, eligible veterans/war widow(er)s may receive:
  • items listed for supply in the PBS
  • items listed under the RPBS, including wound care products
  • items not listed on either the PBS or RPBS schedules, if clinically justified.
  • All medicines supplied under the RPBS are dispensed at the concessional rate (or free if the patient has reached their Safety Net threshold).

reserve/reservist ADF members: ADF members in the active or inactive reserve forces for the Navy, Army or Air Force. Most members leaving full-time service make the transition to the inactive reserve forces, unless there are medical or other grounds preventing this.

risk: The probability of an event occurring during a specified period of time.

service: The three broad arms of the ADF—the Navy, Army and Air Force.

service status: The broad nature of an individual’s employment with the ADF, namely: permanent (previously referred to as serving), reserve and ex-serving.

statistical significance: A statistical measure indicating how likely the observed difference is due to chance alone.

suicide: An action intended to deliberately end one’s own life.

transition: The process of moving from full-time, part-time or reserve ADF service into civilian life.

underlying cause of death: The disease or injury that initiated the train of events leading directly to death; that is, the primary or main cause of death. The underlying cause of death as reported on the National Mortality Database is used to assign the cause of death.

weighting: Adjustment of the characteristics of one group so they are statistically similar to the characteristics of another group so that comparisons of the effect under study can be more certain.