As both men and women age, a decrease in bone density typically occurs. Strength training and a diet rich in calcium and vitamin D can help slow down this process, but nothing can prevent it entirely. Making matters worse for women, according to an article in Women's Health magazine, is the use of oral contraceptives.

Citing a study published in the journal Osteoporosis International, the article points out the potential link between the Pill and a lower degree of bone mineral density. Based on the study, study subjects who had been on birth control pills for an average of 3.5 years had three percent less bone density at the spine and two percent less at the hips.

Researchers aren't sure what causes the Pill to have this effect, but they stress the importance of getting at least 1,000 milligrams of calcium per day and following a resistance training exercise program to help keep bones strong.