Final answer:
The decrease in the death rate among middle-aged adults is largely attributed to a drop in cancer-related deaths, thanks to improvements in medical care and prevention measures. This trend contributes to population aging and the increased need for healthcare services.
Step-by-step explanation:
The death rate among middle-aged adults has decreased largely due to a significant decline in cancer mortality rates. Advances in medical technology, early detection practices, and improvements in treatment have greatly reduced the deadly impact of this disease group. By the recent data, cancer death rates have consistently seen a decrease, resulting in the avoidance of more than 1.3 million cancer deaths over a span of two decades.
As well as the development in healthcare, other factors have contributed to the overall reduction in death rates among the global population. These include a decrease in infant mortality, better handling of infectious diseases, and increased awareness of health and preventive measures. This substantial decline in mortality has been a key factor in prompting population aging, which presents new challenges in healthcare and social services.