Age related increase in impairment across the life course: the use of Zomba curves to estimate assistive technology needs in Malawi

Abstract

Purpose

Global population growth and increasing longevity means that the need for Assistive Technology (AT) will continue to increase. The level of unmet need for AT is greatest in low-income settings. The aim of this study is to identify age-related increase in impairment and to estimate the AT needs.

Materials and Methods

We analysed secondary data from the 2018 Malawi Population and Housing Census (MPHC) based on the Washington Group on Disability Statistics (WG) short-set of questions.

Results

Out of the 1,556,670 persons with one or more functional limitations or disabilities identified in the census, self-reported difficulties in all domains were markedly higher from age 40 and above. The proportion reporting one functional limitation is higher compared to two or more limitations, but at age 78–80 the proportion reporting two or more functional limitations increased above those reporting one functional limitation. Although 60.9% (60.7–61.0) and 63.5% (63.3–63.6) of those who reported difficulty in seeing and hearing were using glasses and hearing aids respectively, the estimated total need for glasses and hearing aids in this group was 98.9% (98.0–99.0) and 98.4% (98.3–98.5) respectively. The unmet need for glasses and hearing aids were therefore 38.1% and 34.9% respectively.

Conclusion

The differential slope of impairment curves against age is a guide to the increasing demand for AT across the life course and across different domains of functioning. Country specific analysis of impairment across age and domains is essential to understand and plan for the growing need for AT globally.

IMPLICATIONS FOR REHABILITATION

• It is important to estimate and plan for impairment across life course to address the age-related increase in impairment and the increasing need for AT with age.

• The Zomba curves show the cumulative nature of impairment with age and the need for age and need specific provision of AT across the life course through proactive policy level actions.

• The significant high unmet need for glasses and hearing aids attests to similar need for other assistive products and the need for setting specific interventions to address needs of affected persons.

• The differential slope of impairment curves against age is a guide to the differing and increasing demand for assistive technology across the life course and across different domains of functioning

Keywords:

• Assistive technology
• assistive products estimation
• life course approach
• Zomba curves

Acknowledgements

The authors are grateful to the members of APPLICABLE Project Action Research Group.

Author contributions

IDE and MM conceptualized the paper with contributions from MZJ, EMS, JK and AM. MZJ analysed the data with contribution from IDE, MM and PC. IDE wrote the initial draft which was reviewed and revised by all the authors. All authors read and approved the final version of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data sharing

The datasets used in the current study are available from the corresponding author on reasonable request.

Additional information

Funding

This work was supported by funding from the Irish Research Council (IRC) grant number-COALESCE/2019/114.