A London newspaper published a report Monday of a woman whose over-use of chemical sunscreen led to the development of adult-onset rickets caused by severe vitamin D deficiency.

“A health conscious nurse has been diagnosed with rickets after covering herself for years with factor 50 sun block,” London’s Mirror reported. “Helen Smith, 38, suffered excruciating joint pain and extreme tiredness for almost a decade before doctors realized what was wrong with her.”

“I was absolutely staggered when I found the cause of all this had been because I was being too responsible in the sun,” Smith told the paper. Her severe vitamin D deficiency went undiagnosed for about 10 years. “I’d get really bad lower back pain which spread to my hips and shoulders. I’d be in terrible pain and unbelievably tired. Some days I couldn’t get out of bed.”

Fair-skinned, she always wore SPF 50 outside — even on days when sunburn was not possible. Visiting a new doctor may have saved her life — the doctor put her on a high vitamin D doage and her pain subsided.

“I thought I was being responsible by putting on sunscreen. I’d never even heard of vitamin deficiency and couldn’t believe I’d done this to myself,” she told the paper. “Now I try and get my 30 minutes of sunlight as soon as the sun comes out, after which I put on factor 15 sunscreen. I don’t want to be that ill again.”

Professor John Monson, of the Endocrinology Centre at the London Clinic, told the Mirror, “Unfortunately we are seeing more instances of insufficiency of vitamin D because people are not spending enough time outdoors.”

To read the Mirror story click here.