Summer in Wisconsin 25. September 2007 William Davis (10) It's been a glorious summer in Wisconsin. For weeks straight, we've enjoyed bright, sunny days with temperatures in the 70s and 80s. Even now, in late September, our windows are wide open and the days are warm and sunny. Yesterday, it was 84 degrees. Yes, it did rain for a stretch of about 10 days in August, but for the most part it has been a wonderfully sunny summer. So it struck Andy as a big surprise when we checked his 25-OH-vitamin D3 blood level: 15 ng/ml--severe deficiency. "I don't get it. I'm outside almost every day. Look at me! How do you think I got this tan?"Indeed, Andy sported a nice dark tan over exposed areas. In fact, Andy was among the dozen or so people this month with deficiencies of this magnitude. Deficiency is not the exception; it is the rule. Of course, if Andy's blood level is at the level of severe deficiency in September, he will only trend lower over the next few weeks and months. He would likely have shown vitamin D blood levels of <10 ng/ml by January--profound deficiency. With deficiency of this severity, Andy has been exposing himself to risk for prostate and colon cancer, diabetes and metabolic syndrome, low HDL, higher triglycerides, higher blood sugars, higher C-reactive protein, osteoporosis, arthritis . . .Correcting the deficiency is easy. But, as you can see, getting sun is not always the answer. Even with an active, outdoor lifestyle and a tan, Andy still remained significantly deficient. Oral replacement with vitamin D3, or cholecalciferol, is an absolute necessity.