DEAR DR. ROACH: I’m a 78-year-old male with a history of high blood pressure, and I had a bovine aortic valve replacement in 2009. I had a negative colonoscopy in 2003, but in 2013, my colonoscopy required a polypectomy of a 3-mm tubular adenoma. In 2019, my colonoscopy was negative again. I’m concerned with the risks involved in repeat colonoscopies. What is your opinion?

— J.G.

ANSWER: The usual recommendation would be to consider a repeat colonoscopy in 2029, when you would be about 82. This is an age where you could decide to stop having colonoscopies, but if you were my patient, I would probably advise you to consider another colonoscopy again, given your history of a tubular adenoma. This is a condition that can progress to colon cancer over the years.

You are right that there are risks of a colonoscopy, but high blood pressure and a valve replacement are not high-risk conditions that would make a colonoscopy too dangerous, in my opinion. If the next colonoscopy were negative again, you could then safely discontinue the colonoscopies as the risk of progressing to colon cancer in your expected lifetime, even if you lived to be over 100, would be very small.

I would respect your decision not to have any more colonoscopies, but in my opinion, the benefit outweighs the risk for most healthy 82-year-olds with a history of premalignant polyps, even if your most recent one didn’t show any polyps.

DEAR DR. ROACH: What is a fever? I mean, when I should worry about my temperature? I usually run slightly below normal.

— A.O.A.

ANSWER: Although 100.4 degrees Fahrenheit is usually considered a fever, this isn’t universally true. Body temperature varies based on the time of day (morning temperatures are lower than afternoon), by age (older people tend to have lower temps), and from person to person.

An increase in a baseline temperature of 1.8-3.6 degrees Fahrenheit could be considered a fever. The “average” person’s temperature has been found to be between 97.9-98.2 degrees Fahrenheit in large trials, so most people are below what has long been considered “normal.” The range of healthy people’s temperatures is quite broad, with 99% of people who were studied ranging from 95.5-99.9 degrees Fahrenheit.

Elevated temperatures often come from infections. Viral, bacterial, fungal and parasitic infections can all cause a fever. However, there are metabolic conditions that cause an elevated blood temperature without an infection. Heat stroke, some medications, very high thyroid hormone levels and bleeding inside the brain can all cause high temperatures, sometimes dangerously high.