- CKDu is a complex health problem with unknown origins
- The disease is especially prevalent among sugarcane workers
- Kidney dialysis and transplants are often too expensive for employees
- Some research on the disease is funded by the sugarcane industry, causing controversy
Juan Salgado was 16 when he started cutting sugarcane, in a town near the Pacific coast of Nicaragua in 1966.
His symptoms began about 35 years later: Fever. Headaches. Poor appetite. Feelings of faintness. For no obvious reason, his kidneys were severely damaged, to the point that doctors said he couldn't do agricultural work anymore. Many of his friends had it worse.
"I know, many, many workers who were colleagues of mine, who have already died, and I know also many who are not capable of working anymore because of the disease," said Salgado, now 65, who worked near the town of Chichigalpa, Nicaragua.
The disease is known by scientists as "chronic kidney disease of unknown origin," or CKDu. In rural communities in Nicaragua, it's "creatinina," the Spanish word for creatinine, a biomarker of kidney strength.
At least 20,000 people have died prematurely from this mysterious disease in Central America in the last two decades, according to one estimate, but the real scope of the problem is unknown. The illness is not related to diabetes or hypertension -- drivers of kidney disease in the United States -- and affects primarily young men.
The disease is concentrated on the Pacific Coast in male agricultural workers, especially those cutting sugarcane. El Salvador, Nicaragua and Costa Rica seem to be hotbeds of the illness.
Scientists believe that a multitude of factors could be contributing to the disease, but that there's likely at least one factor that is job-related. Making matters tricky, the sugarcane industry has been a provider of funding for major studies on the illness, raising concerns that companies could be influencing the results.
In Salgado's opinion, the Nicaraguan sugarcane industry players "know well the cause of this disease."
Jason Glaser, a documentary filmmaker and community advocate, is not as sure. It is not yet clear to scientists and industry leaders what is causing this increased incidence of kidney disease.
La Isla Foundation, which Salgado co-founded with Glaser in 2008, is dedicated to improving the well-being of sugarcane workers with the disease and promoting prevention, and is collaborating with researchers to better understand what's causing this enigmatic illness. The organization is convening a meeting in July with CDC representatives, and researchers from various institutions to explore possibilities for more research.
"This is a complex problem," said Dr. Reina Turcios-Ruiz, resident adviser at the Centers for Disease Control and Prevention's Central America Regional Office in Guatemala. "It's going to take some time to find an answer, but I think it's important that we stick to it."
"None of the scientific investigations that have been made have established a link of causality between the sugar activity in Central America, and therefore our company, and CKD," Ariel Granera Sacasa, spokesperson for Nicaragua Sugar Estates Limited, said in an e-mail. Nicaragua Sugar Estates Limited is the company that owns Ingenio San Antonio, where Salgado worked for decades.
What is CKDu?
In the United States, a typical patient dies of chronic kidney disease their 70s or 80s, said Daniel Brooks of Boston University School of Public Health. But in Central America, men often get it in their 20s or 30s, and die by their 40s or 50s.
There are no early-stage signs. When patients experience symptoms such as fatigue, pain and high blood pressure, "a lot of the kidney function is already gone," said Brooks, who has been studying the illness.
"In order to be able to help people, they (screenings) need to be done on people who are asymptomatic," he said.
Stage 3 is considered chronic kidney disease, Brooks said. Stage 5 is "end-stage" -- where the only way to stay alive is to be on dialysis or get a transplant. Different people progress at different speeds.
Kidney dialysis and transplant -- both expensive undertakings -- are not accessib