Weather forecasts could help predict periods when out-of-hospital cardiac arrests are likely to rise above normal levels by as much as three days in advance, according to a new study by Hungarian researchers.

The study, published in the journal Public Health, found that falling temperatures were among the most significant weather-related factors associated with cardiac arrest. Researchers found that every 1 degree Celsius decline in average daily temperature was linked to an average 1.4% increase in the number of daily out-of-hospital cardiac arrests.

The researchers also found a seasonal difference in cardiac arrest rates. Almost 18% more out-of-hospital cardiac arrests occurred during winter than during summer.

The findings were based on a nationwide analysis of more than 114,000 cardiac arrest cases recorded in Hungary between November 2018 and December 2023. Researchers from Semmelweis University in Budapest, the Budapest University of Technology and Economics and the Hungarian National Ambulance Service compared the cases with daily weather measurements.

The analysis examined several meteorological factors, including temperature, wind speed, air pressure, humidity and air quality.

The researchers found that the risk was not limited to sudden periods of extreme cold. Generally lower temperatures were also associated with higher numbers of cardiac arrests. Rapid changes in temperature could provide another useful warning indicator, with a daily decline of more than 5 degrees Celsius potentially signaling an increase in cases.

One important finding was that the effects of weather changes did not always appear immediately. An increase in cardiac arrests could occur as much as three days after the weather conditions changed.

The researchers said meteorological forecasts could eventually be used to develop early warning systems for periods when cardiac arrest cases are expected to increase. Such systems could help people with cardiovascular disease and their families take additional precautions during higher-risk periods.

Forecasting could also help ambulance services and hospitals prepare for a potential increase in emergency cases, allowing them to adjust staffing and resources when needed.

Out-of-hospital cardiac arrest is a major cause of death in developed countries. In Europe, between 67 and 170 cases occur for every 100,000 people each year, while the survival rate remains below 10%.

Researchers said identifying factors that can signal an approaching rise in cardiac arrests could help emergency services prepare for increased demand. Early warnings could also reinforce the importance of immediate assistance and resuscitation when cardiac arrest occurs.

The study suggests that weather information could eventually become one component of wider efforts to anticipate emergency healthcare demand and improve preparedness for cardiovascular emergencies. However, further work would be needed before such forecasting systems could be used routinely in healthcare settings.

European patients could face longer waits for some new medicines as US efforts to reduce drug prices may encourage pharmaceutical companies to delay launches in lower-price European markets, according to a modelling study published in The Lancet.

The study examined 195 patented medicines that account for about $87.9 billion in annual US spending. Researchers found that for three-quarters of the medicines analysed, the revenue companies could lose from lowering US prices would exceed their combined annual sales in the countries whose prices could be used as references.

The findings raise concerns about the potential impact of President Donald Trump’s most-favoured-nation pricing policy, which seeks to align US drug prices with lower prices paid in other developed countries.

Researchers said pharmaceutical companies could respond by postponing the launch of new medicines in countries with lower prices. Delaying a European launch could prevent those prices from being used as a benchmark for US negotiations.

“Policies in the US may impact access to medicines globally,” said study author Kerstin Vokinger of ETH Zurich and the University of Zurich.

The European Patients Forum warned that patients with serious or progressive illnesses could be particularly affected if companies delay introducing treatments.

Europe has already experienced a decline in new medicine launches. Reuters reported in March that drug launches in EU markets had fallen by about 35 per cent during the 10 months following Trump’s executive order compared with the previous 10 months. Researchers have not established that the US pricing policy directly caused the decline.

Alexander Natz, chief executive of biotech entrepreneurs’ lobby Eucope, said companies were increasingly reconsidering whether and when to launch products in European countries, including Germany.

He said governments may need to consider whether they are prepared to spend more on healthcare to ensure patients have timely access to innovative treatments.

Thomas Hwang of Brigham and Women’s Hospital, the study’s lead author, said countries used as references for US prices, including Germany, Japan and Australia, were already under pressure to increase medicine spending despite limited healthcare budgets.

Exposure to light during sleep, including relatively low levels such as light from a phone screen or through a partially open door, has been linked to potentially harmful changes in the structure and function of the heart, according to a new study.

The research, published in the European Heart Journal, examined whether exposure to different levels of light at night was associated with changes in the heart several years later.

The study involved 11,071 people who were exposed to varying levels of nighttime light for one week. The levels ranged from near total darkness to light comparable with a phone screen at low brightness or light entering through a gap in a door.

Three years after the week of monitoring, participants underwent cardiovascular magnetic resonance scans. Researchers used the scans to assess the structure and function of their hearts.

Those exposed to the highest levels of nighttime light were more likely to show thickening of the walls of the heart’s left ventricle. The change reduced the space available inside the chamber. Researchers also identified signs that the heart had become less able to flex during a heartbeat, which can indicate early impairment in cardiac function.

Lu Qi of Tulane University in New Orleans, who led the research, said higher nighttime light exposure was associated with cardiac remodelling.

Cardiac remodelling refers to changes in the structure and function of the heart that can occur in response to prolonged stress or injury. Qi said the process can eventually weaken the heart and contribute to heart failure.

He said keeping bedrooms as dark as possible should be considered as one possible strategy for preventing cardiovascular disease.

The study’s findings were also discussed in an accompanying editorial by Professor Thomas Münzel of University Medical Center Mainz in Germany and colleagues. They argued that darkness should receive greater recognition as an important factor in cardiovascular health.

The researchers urged doctors to ask patients about their sleeping environments, including how dark their bedrooms are, whether they work night shifts and how much they use screens after sunset.

They suggested practical measures such as installing blackout curtains, choosing warmer-coloured bedside lighting and covering small standby lights on household electronics.

The editorial also highlighted the role of local authorities in reducing light pollution. Cities can use shielded lighting fixtures, warmer-spectrum bulbs and streetlights that dim or activate only when needed.

The authors said these measures could reduce unnecessary nighttime light exposure while also saving energy.

The researchers noted that the findings point to an association between nighttime light exposure and changes in heart structure and function, rather than proving that light exposure directly causes heart disease. Further research will be needed to understand the biological mechanisms involved and determine whether reducing nighttime light can lower cardiovascular risk.