10The global picture & projections to 2050

FThe scale, worldwide

The Global Burden of Disease study estimated that, in 2019, about 1.57 billion people — close to one in five — were living with hearing loss, of whom some 430 million had loss in the moderate-or-worse range that warrants rehabilitation. By this accounting, hearing loss is the third-largest contributor to years lived with disability on the planet. Drag through the projection below to see the trajectory.[2021, 2021]

FTWhy it is rising

The WHO projects that the number with some hearing loss will reach roughly 2.5 billion by 2050, with at least 700 million needing active ear-and-hearing care. The rise is overwhelmingly demographic: the world's population is growing, and — more importantly — ageing, and age-related hearing loss accumulates in the upper decades. Population growth keeps the childhood and noise-related burden large even as prevention chips away at it. The tide is rising for reasons that have little to do with the ear and everything to do with how many people there are and how long they live.[2021]

FTAn unequal burden

The global average conceals a steep gradient. The great majority of people with hearing loss live in low- and middle-income countries, and within every country the burden falls hardest on the poor. The causes track that inequality: the preventable, infective and perinatal causes that dominate India and the developing world are precisely those that wealth and strong health systems have largely eliminated elsewhere. The world's hearing-loss burden is, to a first approximation, a burden of poverty and of youth.

CToo few to treat it

The cruelest part of the inequality is the workforce. The regions with the heaviest burden have the fewest ear-nose-and-throat surgeons and audiologists — in many low-income countries, a mere handful for the entire population. A vast prevalence meeting a tiny workforce produces enormous unmet need: most people who could benefit from a hearing aid, let alone a cochlear implant, never receive one. This mismatch is the subject the chapter closes on (Module 12).[2021]

FIndia in the world

Seen against this backdrop, India is not an exception but a concentrated exampleof the global pattern — a large, young, growing population; a causal mix weighted toward preventable disease; and a hearing-care workforce stretched thin across vast numbers. Understanding the Indian epidemiology, in other words, is a long way toward understanding the world's. The figures may be national, but the lessons are global.

Numbers describe the burden; they do not yet convey what it costs. The next module turns from counting heads to counting the human and economic consequences: the cost of hearing loss (Module 11).