Diseases & Conditions Archive

Some studies suggest a possible link. But don't switch to regular sugary sodas — try infused water instead.

For diet soda fans, recent news reports linking these popular drinks to a higher risk of stroke may have been alarming. A closer look at the study behind the headlines suggests there's no need to panic. But beverages naturally low in calories are probably a healthier option than artificially sweetened drinks.

For starters, observational studies like this one (see "Diet soda and the brain: The latest findings") cannot prove cause and effect. Also, only 97 people had strokes during the 10-year follow-up, which means only two or three of those strokes could possibly be attributed to drinking diet soda, says Dr. Kathryn Rexrode, an associate professor of medicine at Harvard-affiliated Brigham and Women's Hospital who co-authored an earlier, larger study looking at soda consumption and stroke risk.

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Although bone-weakening osteoporosis is quite common among older people, it isn't an inevitable part of aging. There's a lot you can do to shield your bones from this disease.

The best insurance against osteoporosis is building the highest bone density possible by your 30s and minimizing bone loss after that. But if you you're already in midlife or beyond, there is still much you can do to preserve the bone you have and perhaps even to replace lost bone. Daily weight-bearing exercise, like walking, is the best medicine. Getting enough calcium and vitamin D are two other critical strategies for keeping bones strong.

News briefs

A ministroke, or transient ischemic attack (TIA), occurs when blood flow to part of the brain is blocked temporarily. It often causes one or two symptoms of a full-blown stroke — such as sudden face drooping, arm or leg weakness, confusion, slurred speech, or terrible headache — and typically lasts just a few minutes. If you've had a TIA, you are at much higher risk for subsequently suffering a full-blown stroke. So when you have symptoms that might indicate a TIA — or a full-blown stroke — call 911. You may need brain imaging to tell whether a stroke has occurred and what type of stroke it is, so you can get immediate treatment for a stroke. If it's a TIA, you may need additional treatments to prevent a future stroke. Unfortunately, most people who experience symptoms of ministrokes don't call 911 for help, according to results of a survey from the American Heart Association/American Stroke Association (AHA/ASA), published online May 1, 2017. Of the 2,000 people who took the AHA/ASA survey, about 35% said they'd experienced a TIA symptom. But only 3% of that group called 911. As a result, some likely suffered preventable permanent brain damage.

Recent findings raise concerns about lowering diastolic blood pressure — the second number in your blood pressure reading — too far.

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More of us than ever before are taking medications to lower our blood pressure. Longstanding guidelines suggest that most people should aim for a systolic blood pressure (the first number in a reading) no higher than 140 millimeters of mercury (mm Hg). But in 2015, the results of the Systolic Blood Pressure Intervention Trial (SPRINT) suggested that reaching a target of 120 mm Hg could further reduce the risks associated with high blood pressure, including heart attack, stroke, heart failure, and death.

Yet reaching that lower target often requires three blood pressure medications, which can increase the likelihood of side effects. Two observational studies and one clinical trial have raised concerns about lowering blood pressure — particularly diastolic pressure — too far. Diastolic blood pressure (the second number in a reading) represents the pressure between beats when the heart relaxes. "When your systolic blood pressure gets too low, it can manifest as lightheadedness, fainting, and weakness. But low diastolic pressure by itself doesn't have any symptoms," says Dr. Paul Conlin, professor of medicine at Harvard Medical School and chief of medicine at the VA Boston Healthcare System.

On call

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Q. I've noticed recently that I sweat excessively, regardless of the temperature. Should I be concerned?

A. Your genes can determine whether you sweat a lot, but a sudden change in your regular sweating may suggest an underlying condition. Sweating is regulated by your nervous system and can be triggered by a number of causes. The primary signal for perspiration originates in the brain in response to a temperature-related or emotional cue, and then is carried by the autonomic nervous system to the sweat glands in the skin.

A Harvard Medical School doctor answers a common eyesight question

Q: Recently, I started to notice tiny threadlike shapes in my field of vision. My doctor says they are "floaters." Should I be concerned?

A: "Floaters" is a catchall term for what look like dots, threads, or cobwebs drifting across your line of vision.

Ask the doctor

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Q. Several years ago you wrote about a new technology called CRISPR that might make it possible to cure some incurable diseases. I keep hearing about this in the news. Is it any closer to reality?

A. Yes, there has been progress. What does CRISPR stand for? You don't want to know. What does it do? You do want to know, because it's pretty amazing. A colleague here at Harvard Medical School, Dr. George Church, says CRISPR enables a scientist to "edit any piece of any DNA a thousand times more easily and precisely than before, which is game-changing for gene therapies." Why would doctors and scientists want to "edit" DNA? Because disease is caused by genes that are not built properly or are not turned on and off properly. Both problems, theoretically, can be corrected by precisely editing the DNA that makes up those genes.

Three telltale symptoms occur in 75% of all strokes, often in combination. Don't ignore them — even if they're short-lived.

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Every 40 seconds, someone in the United States has a stroke. Also known as "brain attacks," strokes result from an injury to a blood vessel that limits blood flow to part of the brain. Rapid diagnosis and treatment can prevent potentially devastating disability or death — which is why everyone should know the common warning signs of a stroke.

In 2013, the American Stroke Association unveiled a stroke awareness campaign based on the mnemonic FAST. Around that the time, a national survey suggested that 28% of Americans didn't know any stroke symptoms, and nearly half weren't sure what to do if they experienced or witnessed the symptoms of a stroke. But four years later, things seem to be improving.

If you have a hacking cough and breathlessness, don't chalk it up to aging.

Maybe you never smoked, or you stopped decades ago. But you may still be at risk for chronic obstructive pulmonary disease (COPD). That's the umbrella term for a number of lung diseases that sometimes lead to disability and even death. "While about 80% of COPD cases are related to having smoked, 20% are not," says Dr. Bartolome Celli, a pulmonologist with Harvard-affiliated Brigham and Women's Hospital.

Diseases and symptoms

COPD includes emphysema, chronic bronchitis, severe asthma, or a combination of these conditions. They cause inflammation, destruction, or abnormal repair of airways and lung tissue, which reduces airflow and ultimately makes it harder to take in enough oxygen to supply the body.