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Strokes are rising worldwide, a new study shows. And much of the burden is falling on middle-aged adults and low- to middle-income countries. Researchers put together numbers from 119 studies to estimate strokes for the years 1990 and 2010. In that 20-year span, stroke death rates declined 36% in high-income countries and 20% in low- and middle-income countries. But the total number of first strokes rose 68%. Strokes among adults ages 20 to 64 rose from 25% to 31% of all strokes. Most of that increase occurred in the low- to middle-income countries. Illness and death linked with stroke has shifted toward people under age 75, the study found. They now account for 62% of new strokes, 45% of deaths and 72% of illness and disability. Another new study found that hemorrhagic (bleeding) strokes cause 52% of deaths and 61% of disability from stroke.

Blood sugar at the lower end of the normal range may be best for protecting the brain, a new study suggests. The study included 141 older adults. Their average age was 63. None of them had diabetes or pre-diabetes (blood sugar levels that are above normal but below diabetes levels). The study did not include anyone who was overweight or had more than 3.5 alcoholic drinks daily. It also excluded anyone who had been diagnosed with memory and thinking problems. Researchers gave everyone memory tests and measured their blood sugar. Everyone also received a brain MRI scan. Although everyone had blood sugar in the normal range, those with lower levels did better on the memory tests. They also tended to have a larger hippocampus than those with slightly higher blood sugar. This area of the brain plays a major role in memory. The journal Neurology published the study.

Getting a flu shot may decrease your risk of a heart attack, a new study finds. And the benefit is greatest for people with known heart disease. The new research combined the data from 6 studies on flu vaccines. They included nearly 7,000 people. Their average age was 67. About 36% had a history of heart disease. People were randomly assigned to receive flu vaccine or a placebo (fake) shot. Researchers kept track of them for an average of 8 months. In that time, the new study found, those who got the real vaccine were 36% less likely to have a heart attack, heart failure or related problems than those who got the placebo. The new study also took a separate look at just the 3 studies that included people with known heart disease. In these studies, flu shots reduced people’s risk of heart events by 55%. Flu shots are strongly recommended for people with heart disease.