Public debates about women’s safety in India usually focus on violence in public spaces. But there is another dimension of safety that receives far less attention: sanitation security — the ability to access clean toilets safely, privately, and reliably throughout the day. For decades, this issue has been framed primarily as a matter of dignity and gender equality. It is also a public health issue with measurable biological consequences.
One of the least discussed consequences is the possible contribution of sanitation insecurity to kidney stone disease.
Kidney stones form when minerals such as calcium, oxalate, or uric acid crystallize in concentrated urine. The most powerful modifiable risk factor for stones is low urine volume, which is largely determined by fluid intake. Clinical guidelines recommend drinking enough fluids to produce at least 2-2.5 liters of urine per day to reduce stone risk. When urine becomes concentrated, calcium and oxalate crystals are more likely to form.
Yet for millions of women in India, particularly for those working outside the home, drinking water freely has not always been practical.
Before the expansion of household toilets under the Swachh Bharat Mission, women in many parts of rural India adapted their daily routines around sanitation insecurity. Open defecation was often practised early in the morning or after dark to avoid being seen. Numerous studies documented that women frequently restricted food and water intake during the day to avoid needing to urinate when safe facilities were unavailable.
A young woman in Bangalore that I spoke to recently, who has been diagnosed with kidney stones put it this way — “Since I have to get on a train where I can’t use a toilet safely, I have to stop drinking water at least a couple of hours before I leave for the two hour journey. Same on the way home from the office. That means there are many hours in the day where I cannot drink water even when I’m thirsty.”
She is hardly alone. Research on sanitation insecurity in India has found that women often deliberately reduce water consumption or delay urination because toilets are distant, unsafe, or lack privacy. Surveys conducted after household toilets were installed have found that a large majority of women reported no longer needing to restrict food or water intake once a private toilet became available. This behavioural adaptation which leads to chronic mild dehydration is precisely the type of physiological environment that promotes kidney stone formation.
Kidney stones are not rare in India. A study from Ballabgarh in Haryana estimated the lifetime prevalence of urinary stones at about 7.9% in the community. Other epidemiological reviews suggest that roughly 10–12% of Indians may experience kidney stones during their lifetime, with higher prevalence in parts of northern and western India.
These regions are sometimes described as India’s “stone belt.” Higher burdens have been reported in Punjab, Haryana, Rajasthan, Gujarat, Maharashtra, and parts of Uttar Pradesh and Madhya Pradesh. Several environmental and lifestyle factors contribute to the problem.: Hot climates that increase dehydration, groundwater mineral composition in arid regions, dietary shifts toward higher salt and animal protein intake, and the rising prevalence of metabolic conditions such as obesity and diabetes.
Hydration remains central to these risks. When fluid intake drops, urine becomes more concentrated, increasing the supersaturation of calcium oxalate and uric acid crystals that form stones. In simple terms, the chemistry of stone formation reflects the physics of concentration — the less water present, the easier it becomes for crystals to form.
Historically, stones were far more common in men. But the gap has been narrowing worldwide. Several studies across Asia report declining male-to-female ratios in stone disease over the past three decades. In some hospital-based studies in northeastern India, the ratio has approached 1:1, suggesting that women now experience stones nearly as often as men in certain regions. One important reason is that women working in jobs with limited opportunities to drink water or use toilets — such as teachers, nurses, factory workers, drivers, and operating-room staff — are also the ones at greatest risk of dehydration because of the physical nature of their jobs, and face an increased risk of kidney stone formation.
Of course, sanitation insecurity is only one part of the story. Kidney stone risk is also influenced by diet, obesity, metabolic syndrome, genetics, and climate. Rising temperatures and heat exposure can increase dehydration, which in turn raises stone risk. These broader changes help explain why kidney stones are becoming more common, but don’t explain why rates are increasing more in women than in men.
Building toilets is only the first step. Design, usability, and maintenance determine whether they are actually used consistently. India has dramatically expanded toilet construction in recent years, but public facilities are often underused when they lack regular cleaning, reliable water supply, lighting, or privacy — factors that particularly affect women’s willingness to use them. Public sanitation should function less like a one-time construction project, and more like an ongoing service.
Many countries have recognised this challenge and designed around it. In Thailand, for example, public toilets in markets, transport hubs, and public spaces are routinely inspected and graded for hygiene and accessibility, and operators are accountable for maintenance. The result is a system where facilities are clean, usable and trusted.
Public health discussions typically treat sanitation as a tool for preventing infectious diseases including diarrhoea, cholera, and parasitic infections. Although these benefits are real and substantial, sanitation also influences health by shaping everyday habits — when people drink water, how long they wait before urinating, and whether they feel comfortable using available facilities.
Women’s access to secure sanitation, therefore, cannot be separated from health policy. When sanitation systems are designed with safety, privacy, and accessibility in mind, they do more than protect dignity. They shape the daily habits that determine health.
Ramanan Laxminarayan is president, One Health Trust. The views expressed are personal
