Washington, Mar 20 (IANS): After thousands of women reported that breast implants had caused them problems, like debilitating joint pain and fatigue, the US Food and Drug Administration (USFDA) and researchers have started re-examining its safety.

The FDA has begun to re-examine questions about implant safety that have long been disputed by doctors and implant manufacturers, and that most consumers thought had been resolved a decade or so ago, reported The New York Times.

This may be a long-awaited moment of validation for tens of thousands of women who were brushed off as neurotic, looking to cash in on lawsuits or just victims of chance who coincidentally became ill while having implants.

Millions of women used implants, which are silicone sacs filled with either salt water or silicone gel, to enlarge the breasts cosmetically or to rebuild them after a mastectomy for breast cancer.

On Tuesday, the agency warned two makers of breast implants that they had failed to conduct adequate long-term studies of implants' effects on women's health.

Those studies were mandated as a condition of approving the implants, and the agency cautioned devices could be taken off the market if the research wasn't properly carried out.

The agency also issued a statement on Friday, which applied to a broad array of medical devices, acknowledging implanted devices may make some people sick.

"A growing body of evidence suggests a small number of patients may have biological responses to certain types of materials in implantable or insertable devices," the agency said.

Those effects can include "inflammatory reactions and tissue changes causing pain and other symptoms that may interfere with their quality of life."

The FDA said it was gathering data to fill information gaps in the science "to further our understanding of medical device materials and improve the safety of devices for patients."

Silicone, used in implants, is one of the materials under scrutiny.

The agency will hold a two-day meeting next week about breast implants, hearing from researchers, patient advocacy groups and manufacturers.

About 400,000 women in the US get breast implants every year, including 300,000 for cosmetic reasons and 100,000 for reconstruction after mastectomies to treat or prevent breast cancer.

Worldwide, about 10 million women have breast implants.