BIOMEDICAL CHALLENGES OF HUMAN SENESCENCE: A REVIEW

Abstract

Objective: To summarise and discuss the progress made in the study of human senescence
over the past one hundred years and assess the achievements to date.
Data sources: Published original research and reviews during the past one hundred years.
Study selection: The summary focused on those contributions that tested the various
hypotheses that attempt to identify and explain the factors that are involved in the ageing
process.
Data extraction and synthesis: Online and manual library searches provided a body of
data on which the summaries and discussions were based. Specific questions were
addressed: Why does ageing occur? What are the key mechanisms? To what extent
are genetic and environmental factors involved in the ageing process? How does the
immune system behave during ageing and especially against infectious agents? Answers
to these questions were discussed against the background of major improvements in
life expectancy in most parts of the world except for sub-Saharan Africa where the
HIV/AIDS pandemic has reversed the trend.
Conclusion: Biological and clinical studies over the past century clearly reflect a better
understanding of the major factors involved in human senescence. It is appreciated that
human life expectancy has improved dramatically over the period through achievements
in public health, therapy, nutrition and general living standards. A great deal remains
to be done through multidisciplinary research before the quality of life can be improved
further.