Science news that says how sure we are.

• Health & medicine · 5 October 2026

  Air purifiers sped a brain test only after researchers sorted by age

  Across 119 people living beside highways in Somerville, Massachusetts, a month of HEPA filtration made no overall difference on a timed connect-the-dots test. When the researchers split the group at age 40 after the fact, the 50 older participants finished the harder half about 7 seconds faster. That's about the gain from one retake of the test, though the design balances practice across months. Brain function in daily life wasn't measured.

  Over-40s finding: SpeculativeEveryone: EarlyPopular claim: Overstated

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• Health & medicine · 5 October 2026

  Five-cup coffee warning for older women's bones rests on a faint curve

  In about 8,000 US women over 65, followed for roughly eight years, coffee drinkers and non-drinkers showed no clear difference in hip bone density. Above five cups a day a fitted curve drifted lower, but not clearly beyond chance, and the paper doesn't say how many women drank that much. Tea drinkers' hips were 0.003 g/cm² denser, less than a year's worth of normal age-related loss. Fractures weren't studied.

  Tea: Early, close to SpeculativeCoffee drinkers vs non-drinkers: Promising, close to EarlyOver five cups: Speculative
• Health & medicine · 5 October 2026

  Across 46 trials, vitamin D pills didn't cut fractures or falls

  A review of 69 trials and 153,902 adults found that 6.5% of people broke a bone whether they took vitamin D or a dummy pill. Calcium and vitamin D together did slightly better, about 1 fewer fracture per 100 people, mostly thanks to one 1992 trial in French care homes. Most volunteers lived at home and weren't short of vitamin D; people who are truly deficient were barely tested.

  Vitamin D, fractures: SolidVitamin D, falls: SolidCalcium + D, fractures: Promising, close to Early