Doc: Does cow’s milk make strong bones — or weak ones?
Dear Dr. Roach: I read that cow’s milk weakens the bones. Is that true?
Dear A.H.: The preponderance of the evidence is that dairy intake — like cow’s milk, yogurt and cheese — increases bone strength and reduces fracture risk. However, there is not the highest level of evidence to support this. In absence of interventional data (where one group is given cow’s milk and the other given something else), we have to rely on other kinds of evidence, all of which have some potential for bias.
Some of these have shown benefit from drinking cow’s milk; others have not. A 2018 study from the U.S. estimated a 6 to 8 percent reduction in fracture risk from consuming cheese or milk daily. It’s not clear whether it’s the calcium, the vitamin D or something else that may be reducing risk.
Regular exercise is another way to reduce risk of osteoporosis and fractures. Unfortunately, some people will still be at risk for fractures despite an excellent diet and regular exercise, so those at high risk should be screened, and may require medication. You can reduce your chances of needing medication through a good lifestyle.
Dear Dr. Roach: Do all cervical cancers come from HPV?
Dear B.H.: One study estimated that 99.7 percent of all cervical cancers worldwide are due to infection from human papillomavirus, especially the high-risk strains that are most likely to cause changes in the cells that can become cancerous. However, most cases of HPV are effectively treated by the body, and do not become cancer.
A few cancers do not have evidence for HPV when they are looked at. In one recent study from the U.S., about 10 percent of cervical cancers did not seem to be associated with HPV, but on careful re-evaluation, about half of those did have an association with HPV. Still, there are some cases of cervical cancer that are not due to HPV, and the risk factors for those may include smoking and HIV. This type of cervical cancer has a worse prognosis than HPV-related cervical cancer.
Population-level vaccination of HPV is likely to dramatically reduce cervical cancer, but not eliminate it entirely. For this reason, the Pap smear, which diagnoses cancer and its precursors, is likely to remain an important screening tool.
Dear Dr. Roach: I am an 89-year-old widow trying to stay in my home with the help of my daughter. Six months ago, I had a bad fall and went to the hospital, where I got all kinds of tests and lots of information from several doctors. A neurologist said I had two or three aneurysms in my head, but treatment might cause more harm than good. Now home, my primary doctor is trying to help my anxiety. He gave me Zoloft, but I got depressed. He wants to try Effexor, but the instruction sheet mentioned that bleeding might occur. Should I avoid this medicine?
Dear J.M.G.: Venlafaxine (Effexor) has been shown to increase the risk of bleeding, with only a slight risk for most people. However, bleeding from a brain aneurism is very dangerous, so I think I would avoid that particular drug. There are alternatives that don’t have that risk. Even if the risk is slight, worrying about a drug’s possible side effects isn’t going to make your anxiety better.
Email questions to ToYourGoodHealth@ med.cornell.edu.