For women older than 50 who have been confused by conflicting advice on how frequently to get a mammogram, some new science is here to guide their decisions. A study in the Annals of Internal Medicine concludes that a woman’s breast density should influence the frequency with which she is screened for breast cancer, in addition to long-recognized breast cancer risk factors such as age, ethnicity, personal history of abnormal breast findings and a family history of breast cancer. The research recommends that women older than 50 with dense breast tissue who have higher-than-normal risk of developing breast cancer should get annual mammograms — twice as often as the current standard. Women with average risk and low breast density could go as long as three years between mammograms.

Living near fracking site linked to illnesses

Living near a natural gas hydraulic fracturing site is associated with increased rates of sinus problems, migraines and fatigue, according to new research. Scientists ranked 7,785 participants according to how close they lived to fracking sites and larger wells. Compared with those in the bottom quarter by this measure, those in the top quarter were 49 percent more likely to have sinusitis and migraines, 88 percent more likely to have sinusitis and fatigue, 95 percent more likely to have migraines and fatigue and 84 percent more likely to have all three symptoms.

Moderate drinking doesn’t hurt fertility

A study has found that moderate alcohol consumption does not affect a woman’s ability to get pregnant, although higher amounts might. Researchers studied 6,120 women trying to conceive in stable relationships with male partners. The women reported their drinking habits in questionnaires. By the end of the study, 4,210 of the women had gotten pregnant. Women who drank the alcoholic equivalent of one to 13 4-ounce glasses of wine a week were no less likely to conceive than those who abstained completely. Heavier drinking was associated with an 18 percent decrease in fecundity.

Cancer now top cause of death in 22 states

Cancer has surpassed heart disease as the leading cause of death in California and 21 other states, according to a report from the Centers for Disease Control and Prevention. That total is in stark contrast to the situation at the start of this century, when only two states — Alaska and Minnesota — lost more people to cancer than heart disease. Nationwide, heart disease still edges out cancer as the top killer of Americans. In 2014, 614,348 U.S. residents died of heart disease, compared with 591,699 who succumbed to cancer, according to the CDC.