We all get a dry mouth occasionally.
Maybe you’re stressed, anxious, about to give a big presentation. Maybe you’ve had a busy day, and staying hydrated hasn’t been your first priority. Maybe you’ve knocked back one too many long blacks, and you’re in dire need of some water and a breath mint.
For some people, though, feelings of a dry mouth, tongue and throat aren’t just momentary – they’re severe, chronic, and potentially life-changing. Persistent dry mouth can lead to a wide variety of physical and psychological impacts, and can seriously compromise quality of life.
Unfortunately, the chance of developing dry mouth (xerostomia) increases as we get older. In this article, we’re going to look at what dry mouth is, as well as exactly why it’s so common in older people.
What is dry mouth?
Dry mouth occurs when your mouth doesn’t feel moist. Often, this is because your salivary glands aren’t producing enough saliva to keep the inside of your mouth wet, a condition known as ‘hyposalivation’.
Saliva is essential for everyday tasks like speaking, eating, and swallowing, so many people with dry mouth experience reduced quality of life. If not managed properly, dry mouth can also lead to a variety of different oral health conditions, like bad breath, gum disease, and tooth decay, as well as conditions like malnutrition [1, 2].
What is responsible for dry mouth in older adults?
Although dry mouth can impact anyone, it’s most common in certain groups of people. These include :
- Older adults (aged 65+ years)
- People with certain health conditions, Sjögren’s syndrome or rheumatoid arthritis
- Chronic alcohol, cigarette and drug users
- People with diabetes
- People who have had treatment for head or neck cancer
- People with chronic anxiety
Almost half of older adults are estimated to live with dry mouth, as compared to less than 20% of people in their early thirties . Although the exact causes of dry mouth vary from person to person, taking lots of medication, living with other health conditions, and even just getting old can all be contributing factors to dry mouth.
Let’s take a look at each of those causes in turn.
The older we get, the more health conditions we live with. This, in turn, means we’re likely to get prescribed lots of different medications to manage or treat those conditions. Taking five or more different types of medication is known as ‘polypharmacy’ .
Polypharmacy has been strongly linked to a greater risk of dry mouth, with researchers estimating that dry mouth was 27–30% more prevalent in medicated than non-medicated populations .
So how common is polypharmacy? Well, very. An estimated 30% of adults aged over 65 years take five or more medications . In aged care homes, the average resident takes seven to eight different medications each month, with 40% of residents taking more than nine medications .
Unfortunately, dry mouth isn’t the only consequence of polypharmacy. Consuming an excessive amount of medication has also been linked to cognitive impairment, delirium, falls, frailty, urinary incontinence, and weight loss, so, if you think you or a loved one could be taking too many medications, talk to your medical practitioner about the possibility of cutting back .
It’s important to understand that simply taking multiple drugs won’t cause dry mouth – it’s the mechanisms and interactions of those drugs that can impact how your mouth feels. Not every drug is xerogenic (causes dry mouth). Here are some of the most common types of xerogenic drugs [6, 9, 10]:
- Antipsychotics and anticonvulsants
- Anxiolytics and sedatives
- Dopamine agonists
- Cardiovascular medications
- Antiretroviral drugs
- Antidiabetic drugs
You can read more about medications and dry mouth here.
Radiation therapy for head and neck cancer is also a major cause of dry mouth. Because radiation therapy can affect both tumorous and healthy cells, including the cells in your salivary glands, it’s common for people who have undergone treatment to produce less saliva. Modern radiation therapy methods cause dry mouth in about 40% of patients .
Illness & Injury
Illness and injury are also common causes of dry mouth. Pre-existing health conditions can impact both how much saliva we produce and how our mouths feel, contributing to the formation of dry mouth.
One of the most common? Sjögren’s syndrome. This immune disorder manifests as dry mouth and dry eyes, along with joint pain, swollen salivary glands, fatigue, and skin dryness . An estimated 40% of all dry mouth cases in older people are attributed to Sjögren’s syndrome .
Other health conditions that can cause or worsen dry mouth include :
- Parkinson’s disease
- Any injuries or operations to the mouth, neck or throat
- Thyroid disease
- Hepatitis C
- Epstein-Barr virus
- Human T-lymphotropic virus Type 1
- Rheumatoid arthritis
- Primary biliary cirrhosis
- End-stage renal disease
- Ectodermal dysplasia
- Chronic graft-versus-host disease
Age-Related Saliva Reduction
Although most instances of dry mouth in older adults can be linked to either medication or other health conditions, research has shown that age-related physiological changes can also affect saliva production.
Our saliva is produced by three major salivary glands (the parotid, submandibular and sublingual glands), and many minor ones . Within these glands, acinar cells are responsible for secreting saliva . As we age, the percentage of fat and fibrovascular tissue in our major salivary glands increases, while the percentage of acinar cells decreases . Essentially, this can lead to less saliva and narrower, less effective salivary glands.
Age also decreases the number of olfactory and taste receptors in our mouths, which can make stimulating our salivary glands more difficult .
One 2015 review found that both stimulated and unstimulated salivary flow rates were lower in older adults, with stimulated salivary flow rates an average of 66% lower . Interestingly, the lowered flow rates were only present in the submandibular and sublingual glands; both the parotid and minor gland flow rates were unaffected by age .
Age-related changes can also compromise our saliva itself. Mucins are an essential component of saliva – they’re a big part of how it protects our mouths. Unfortunately, as we age, the percentages of mucins MUC1 and MUC2 in our saliva become significantly lower . This increases the risk of oral health conditions, and can cause our mouths to feel dry .
Dry mouth is a complex condition, but one thing is certain: the older we get, the more likely we are to develop dry mouth. The three main causes are:
- Illness and injury
- Age-related saliva reduction
If you or a loved one are experiencing xerostomia, there are plenty of ways to get your mouth moist again, including better hydration, better food choices, and topical treatments like Osmist dry mouth spray. Find out how to manage your xerostomia, and get on top of your oral hydration.
 Han, P., Suarez-Durall, P. & Mulligan, R. (2015) Dry mouth: A critical topic for older adult patients. Journal of Prosthodontic Research. 59(1), 6–19. DOI: 10.1016/j.jpor.2014.11.001
 Xu, F., Laguna, L. & Sarkar, A. (2019) Ageing related changes in quantity and quality of saliva: Where do we stand in our understanding? Journal of Texture Studies. 50(1), 27–35. DOI: 10.1111/jtxs.12356
 Millsop, J. W., Wang, E. A. & Fazel, N. (2017) Etiology, evaluation, and management of xerostomia. Clinics in Dermatology. 35(5), 468–476. DOI: 10.1016/j.clindermatol.2017.06.010
 Mortazavi, H., Baharvand, M., Movahhedian, A., Mohammadi, M. & Khodadoustan, A. (2014) Xerostomia Due to Systemic Disease: A Review of 20 Conditions and Mechanisms. Annals of Medical and Health Sciences Research. 4(4), 503–510. DOI: 10.4103/2141-9248.139284
 Masnoon, N., Shakib, S., Kalisch-Ellet, L. & Caughey, G. E. (2017) What is polypharmacy? A systematic review of definitions. BMC Geriatrics. 17(230). DOI: 10.1186/s12877-017-0621-2
 Barbe, A. G. (2018) Medication-Induced Xerostomia and Hyposalivation in the Elderly: Culprits, Complications, and Management. Drugs & Aging. 35, 877–885. DOI: 10.1007/s40266-018-0588-5
 Kim, J. & Parish, A. L. (2017) Polypharmacy and Medication Management in Older Adults. Nursing Clinics of North America, 52(3), 457–468. DOI: 10.1016/j.cnur.2017.04.007
 Saraf, A. A., Petersen, A. W., Simmons, S. F., Schnelle, J. F., Bell, S. P., Kripalani, S., Myers, A. P., Mixon, A. S., Long, E. A., Jacobsen, J. M. L. & Vasilevskis, E. E. (2016) Medications associated with geriatric syndromes and their prevalence in older hospitalized adults discharged to skilled nursing facilities. Journal of Hospital Medicine. 11(10), 694–700. DOI: 10.1002/jhm.2614
 Cockburn, N., Pradhan, A., Taing, M. W., Kisely, S. & Ford, P. J. (2017) Oral health impacts of medications used to treat mental illness. Journal of Affective Disorders. 223, 184–193. DOI: 10.1016/j.jad.2017.07.037
 Sreebny, L. M. & Schwartz, S. S. (1997) A reference guide to drugs and dry mouth – 2nd edition. Gerodontology. 14(1), 33–47. DOI: 10.1111/j.1741-2358.1997.00033.x
 Strojan, P., Hutcheson, K. A., Eisbruch, A., Beitler, J. J., Langendijk, J. A., Lee, A. W. M., Corry, J., Mendenhall, W. M., Smee, R., Rinaldo, A. & Ferlito, A. (2017) Treatment of late sequelae after radiotherapy for head and neck cancer. Cancer Treatment Reviews. 59, 79–92. DOI: 10.1016/j.ctrv.2017.07.003
 Al-Hashimi, I. (2005) Xerostomia Secondary to Sjögren’s Syndrome in the Elderly. Drugs & Aging. 22(11), 887–899. DOI: 10.2165/00002512-200522110-00001
 Vissink, A., Spijkervet, F. K. L. & Amerongen, A. V. N. (1996) Aging and saliva: A review of the literature. Special Care in Dentistry. 16(3), 95–103. DOI: 10.1111/j.1754-4505.1996.tb00842.x
 Affoo, R. H., Foley, N., Garrick, R., Siqueira, W. L. & Martin, R. E. (2015) Meta-Analysis of Salivary Flow Rates in Young and Older Adults. Journal of the American Geriatrics Society. 63(10), 2142–2151. DOI: 10.1111/jgs.13652