Reports from different sources have recently highlighted that there is a difficulty in using one set of statistics to indicate health improvements.
The Global Burden of Disease (GBD) study, published in The Lancet in 2012, involved a large, multi-national analysis of health improvements throughout the world. The study revealed some mixed findings.
There’s little doubt that longevity is still increasing – significantly throughout the world and dramatically in developing countries. Life expectancy, for example, has increased on average by 11.1 years for males and 12.1 years for females since 1970. As one might expect, the biggest gains have been in developing countries, where the initial baseline was low to start with.
Furthermore, in addition to global mortality, morbidity data was also tracked over time through the use of a measure of disability-adjusted life years (or DALYs). The DALY is an index, not just of mortality but also of the number of ‘healthy’ years lost due to disease or disability.
The data suggests that if developing countries are to follow the path of developed nations, lifestyle-related chronic diseases will soon start to take over from the infectious diseases and injuries that might have dogged countries in their early development.
Yes, data from developed countries, such as Australia, suggests that we are no doubt living longer. However, the data (which uses measures of DALYs) also highlights an important question: are we, in fact, living better?
Chronic diseases, most of which are largely preventable, now make up approximately 60% of all diseases presenting to primary care. Almost 3 in 4 Australians over the age of 20 years have at least one chronic disease and 1 in 2 require management for multiple co-morbidities.
While one might expect chronic diseases to be more prevalent in our society given that we are living longer, the data actually indicates that DALYs have increased across all age cohorts from age 15 years. Only in the children under 5 year olds have DALYs decreased in the last 20 years.
More surprising is the data published in a recent Journal of the American Medical Association report based on US data collected from two cohort groups aged 46-64 years, which was reported in the Nutrition and Health Examination Surveys (NHANES) in 1988-94 and 2007-2010.
The ages of each group meant that the latter survey would be represented by the post-war baby boomers who are now 46-64 years of age; and the former survey by those old enough to be their parents.
Perhaps unexpectedly, the parents did better health-wise at the same age than the boomers, despite the longer life expectancy of the latter. Boomers have higher rates of chronic disease, more disability and lower self-rated health than members of the previous generation at the same age (see Table 1). This is emphasized by the higher rates of hypertension, hypercholesterolemia, diabetes and obesity in the Boomers group.
The authors of the study, led by Dr Dana King from the West Virginia School of Medicine, conclude from this that: “Given the link between positive healthy lifestyles and subsequent health in this age group, the present study demonstrates a clear need for policies that expand efforts at prevention and healthy lifestyle promotion in the baby boomer generation.”
The findings point to the futility of using just one measure of health improvement (mortality), as we have been forced to do in the past, due to limitations of data.
What appears, at the outset, to add confusion to these data is the worldwide obesity epidemic. Over 1 billion people throughout the world are now classified as overweight or obese. The often-quoted link between obesity and early demise has given rise to suggestions that the current generation of overweight and obese adolescents (up to 30% in Australia) may lead shorter lives than their parents.
Predictions that 1 in 3 children born in this millennium will also develop type 2 diabetes in their lifetime – an obesity-related disease – and the link with diabetes and early death, would also suggest a decline in future longevity. The GBD data doesn’t support this.
Longevity continues to increase throughout the world, in spite of the growth in chronic disease and disabilities. Is it then that obesity is a blunt instrument as a measure of disease? After all, 1 in 3 obese have no health risks, yet 1 in 4 of the lean have all the metabolic risks expected of the obese.
Could obesity be, as reported in this column before, just a ‘canary in the mineshaft’ warning of bigger problems in the world around us? (More on this later) Meanwhile, chronic disease is the tsunami, which should concern us – irrespective of obesity’s link with this, and (even more) irrespective of improvements in longevity.
Health Outcome Boomers Parents
Excellent’ health 3.2% 32%**
Use walk device 6.9% 3.3%**
Functional limitation 13.5% 8.8%**
% Obese 38.7% 29.4%**
Get regular exercise 35% 50%**
No regular phys activity 52.2% 17.4%**
Hypertension 43% 36.4%**
Hypercholesterolemia 73.5% 33.8%**
Diabetes 15.5% 12%**
Smokers 21.3% 27.6%**+
Moderate drinking 67.3% 37.2%**
Emphysema 2.3% 3.5%*+
Have had MI 3.6% 5.3%**+
References
King DE, et al. The Status of Baby Boomers’ Health in the United States: The Healthiest Generation? JAMA Internal Medicine. 2013;173(5):385-386.
Wang H, et al. Age-specific and sex-specific mortality in 187 countries, 1970–2010: a systematic analysis for the Global Burden of Disease Study 2010. The Lancet. 2012; 380: 2071–2094.
