Archive · 31 Oct 2025
Lancet Study: 1 in 19 Tamil Nadu Farm Workers Have Chronic Kidney Disease
Imagine tiny filters in your body that clean your blood, called kidneys.
Sometimes, these filters can get damaged over time, and this is called chronic kidney disease.
A big study in Tamil Nadu looked at farm workers, who often work outside in the heat.
They found that about 1 out of every 19 farm workers has this kidney problem.
What's more, for about half of them, doctors can't figure out the usual reasons like sugar or high blood pressure.
This suggests there might be other causes, possibly related to working hard in the heat.
The study also noticed that people who work longer hours outside, especially when it's very hot, were more likely to have kidney issues.
Scientists are suggesting new rules to help protect these workers, like making sure they have enough water and rest breaks when it's too hot, to prevent long-term damage to their kidneys.
A Lancet study found 5.31% of agricultural workers in Tamil Nadu have chronic kidney disease.
Approximately half of these cases are 'Chronic Kidney Disease of Unknown Etiology' (CKDu), not linked to diabetes or hypertension.
The research involved 3,350 adults and used a two-phase testing approach during hot and cool seasons.
Factors like age, diabetes, hypertension, lack of education, anemia, tobacco use, and long outdoor work hours are associated with increased risk.
Heat stress is identified as a significant factor, with higher disease prevalence observed in hotter regions of the state.
- Who
- Agricultural workers in Tamil Nadu
- What
- A study found 5.31% prevalence of chronic kidney disease, with about half of cases being of unknown etiology (CKDu).
- When
- The study's data collection occurred during two rounds, one in the hot August 'second summer' and a follow-up three months later in cooler December.
- Where
- Tamil Nadu, India, across five agroclimatic zones.
- Why
- The study aimed to determine the prevalence of chronic kidney disease among agricultural workers and investigate potential contributing factors, including heat stress.
Study Findings & Recommendations
Study Limitations & Future Research
Prevalence and Cause of CKD
Study Findings & Recommendations
The study definitively found a 5.31% prevalence of chronic kidney disease among agricultural workers, with about half of these cases being of unknown etiology (CKDu).
Study Limitations & Future Research
The paper candidly admits limitations, stating the study was not explicitly designed to measure environmental exposures like heat stress or agrochemical use, which limits the ability to establish causal pathways.
Role of Heat Stress
Study Findings & Recommendations
Heat emerged as a plausible driver, with the map of heat lining up with the map of disease, showing the highest prevalence in the hottest regions and suggesting interventions related to heat exposure.
Study Limitations & Future Research
While the relationship between heat stress and kidney disease is not proven beyond doubt, the authors acknowledge that further interventional studies are needed to confirm the effectiveness of strategies like water, rest, and shade (WRS).
Study Design
Study Findings & Recommendations
The study employed a rigorous statewide sweep with a two-phase confirmation over three months, using stratified multi-stage cluster sampling to select a representative population.
Study Limitations & Future Research
The study is a snapshot and not a long-term follow-up; ultrasounds, biopsies, and urine albumin-to-creatinine analysis were not done universally, and field heat or chemical exposures were not directly measured.
- Study Prevalence
- 5.31% of agricultural workers in Tamil Nadu have chronic kidney disease
- CKDu Cases
- About half of the chronic kidney disease cases lack standard medical explanation (diabetes/hypertension)
- Study Population
- 3,350 adults across Tamil Nadu's agricultural regions
- Methodology
- Two-phase testing (hot season and cool season) to confirm persistent kidney issues
- Risk Factors
- Increased age, diabetes, hypertension, lack of education, anemia, smokeless tobacco use, and long outdoor work hours
- Heat Impact
- Highest prevalence (7.7%) in the hotter north-east zone, lowest (2.16%) in the cooler north-west