University of Oulu

THURSDAY, June 6, 2024 -- Being overweight in adolescence or early adulthood is associated with an increased risk for cerebrovascular disease among women, according to a study published online June 6 in Stroke . Ursula Mikkola, from the University of Oulu in Finland, and colleagues conducted a prospective cohort study to examine the effect of body mass index (BMI) and its changes in adolescence and young adulthood (ages 14 and 31 years) on early-onset cerebrovascular disease through age 54 years in a study including 10,491 people. During follow-up, 452 individuals (4.7 percent) experienced cerebrovascular disease. The researchers found that compared with normal weight, the risk for ischemic cerebrovascular disease was increased at ages 14 and 31 years for women with overweight (hazard ratios [95 percent confidence intervals], 2.49 [1.44 to 4.31] and 2.13 [1.14 to 3.97], respectively) and obesity (hazard ratios [95 percent confidence intervals], 1.87 [0.76 to 4.58] and 2.67 [1.26 to 5.65], respectively). The results were independent of BMI at earlier or later time points. Men did not have similar associations. Women and men with obesity had an increased risk for hemorrhagic cerebrovascular disease at age 31 years (hazard ratios [95 percent confidence intervals], 3.49 [1.13 to 10.7] and 5.75 [1.43 to 23.1], respectively). At age 14 years, the risk for any cerebrovascular disease related to overweight was 2.09 times higher among girls than boys. At age 31 years, the risk for ischemic cerebrovascular disease related to obesity was 6.96 times higher among women than men. "The association between childhood overweight and adult cerebrovascular disease is independent of overweight or obesity in adulthood, highlighting the importance for children to achieve and maintain healthy weights," the authors write. Abstract/Full Text Editorial Whatever your topic of interest, subscribe to our newsletters to get the best of Drugs.com in your inbox.

Women with excess weight at age 14 or 31 may have increased ischemic (clot caused) stroke risk before age 55. The same ischemic stroke risk was not found in men. Losing excess weight after adolescence may not eliminate the stroke risk. In an analysis of more than 50 years of health data, women who had overweight or obesity at age 14 or 31 were more likely to have an ischemic (clot-caused) stroke before age 55, according to research published today in Stroke, the peer-reviewed scientific journal of the American Stroke Association, a division of the American Heart Association. According to the American Heart Association, an ischemic stroke occurs when a vessel supplying blood to the brain is obstructed. Ischemic stroke is the most common type of stroke and accounts for about 87% of all strokes. The study conducted in Finland suggests that women with overweight at age 14 were associated with later clot caused stroke risk despite having lost weight by age 31. Also, women with overweight at age 31 were associated with later clot caused stroke risk despite having been normal weight at age 14. An increased risk of clot caused stroke was not found in men who were overweight at ages 14 or 31. However, men with obesity at age 31 had a higher risk of bleeding stroke compared to women with obesity at age 31. "Our findings suggest that being overweight may have long-term health effects even if the excess weight is temporary," said lead study author Ursula Mikkola, B.M., an investigator in the Research Unit of Population Health at the University of Oulu in Finland. "Health care professionals should pay attention to overweight and obesity in young people and work with them to develop healthier eating patterns and physical activity. However, conversations with teens and young adults about weight should be approached in a non-judgmental and non-stigmatizing manner." To analyze the association between weight at different ages and the risk of stroke before age 55, the researchers reviewed long-term data from participants in the Northern Finland Birth Cohort 1966. The Northern Finland study group was initiated to help understand factors related to preterm birth and infant deaths. In 1966, more than 12,000 pregnant women were enrolled from two northern provinces in Finland. More than 10,000 offspring, now in their 50s, have been followed ever since, with their health information used in multiple research studies. For this analysis, researchers used the body mass index (BMI), a ratio of weight to height, to explore whether those who were overweight or obese at age 14 or age 31 had a different risk of early stroke compared to peers who were not overweight or obese at age 14 or 31. About 1 in 20 participants experienced a clot-caused stroke or transient ischemic attack (TIA, or mini-stroke) during the average follow-up period of almost 39 years after the age 14 evaluation and almost 23 years after the age 31 evaluation. The current study's analysis ended in 2020. Assessing the impact of periods of excess weight on stroke risk, the researchers found: It is important to note that weight is not the only health factor that impacts stroke risk. Many other factors affect stroke risk and should be considered in addition to weight. "By living a healthy lifestyle (eating better, not smoking, healthy sleep, managing blood pressure, cholesterol and blood glucose levels, avoiding excess alcohol use and being physically active), you can lower your risk of stroke even if you were overweight when you were younger," Mikkola added. Researchers do not know why the association of increased risk for clot-caused stroke was not found in men. Researchers are currently investigating the potential causes as well as other risk factors in more detail. In an accompanying editorial Larry Goldstein, M.D., FAHA, notes, "This study provides additional evidence of an association between overweight/obesity and stroke in young adults. However, while it is tempting to assume that reductions in overweight/obesity in younger populations would translate to lower stroke rates in young adults, this remains to be proven." Goldstein is an American Heart Association Stroke Council member and chair of the department of neurology and co-director of the Kentucky Neuroscience Institute, University of Kentucky HealthCare in Lexington, Kentucky. Study details, background and design: Limitations of the study include that it is an analysis of health data (an observational study) and, therefore, it cannot prove a cause-and-effect relationship between weight and early stroke risk. Participants were all born in Finland, so the results may not be generalizable to people in other countries. "Stroke at a young age is rare, so the difference of just a few strokes could have an outsized impact on the risk estimates," Mikkola said. "Also, BMI relies solely on a person's height and weight, therefore, a high BMI may be a misleading way to define obesity, especially in muscular people who may carry little fat even while weighing more."

A research group was able to measure a spike in radiocarbon concentration of trees in Lapland that occurred after the Carrington flare. This discovery helps to prepare for dangerous solar storms. A research group coordinated by the University of Helsinki was able to measure a spike in radiocarbon concentration of trees in Lapland that occurred after the Carrington flare. This discovery helps to prepare for dangerous solar storms. The Carrington Event of 1859 is one of the largest recorded solar storms in the last two centuries. It was seen as white light flares on a giant sunspot group, fires at telegraph stations and disturbances in geomagnetic measurements, as well as aurorae even in tropical regions. In a joint study carried out by the University of Helsinki, Natural Resources Institute Finland and the University of Oulu, a sign of an increase in radiocarbon concentrations following the Carrington storm was detected for the first time in tree rings. Previously, radiocarbon traces have only been detected from far more intense solar storms. Discovery through a cosmic marker Encounters between strong magnetised clouds of charged particles released from the Sun, known as solar plasma flows, and Earth's geomagnetic field result in geomagnetic storms. The geomagnetic field directs the solar storm particles into the atmosphere primarily through the Polar regions. The most visible consequence of the phenomenon are aurorae. In the upper atmosphere, sufficiently high-energy particles can, through nuclear reactions, also produce radiocarbon (14C), a radioactive isotope of carbon. Over the course of months and years, radiocarbon ends up in the lower atmosphere as part of atmospheric carbon dioxide, and eventually in plants through photosynthesis. The process of photosynthesis preserves the information contained in carbon dioxide in the annual rings of trees. To obtain the information held by radiocarbon, samples are extracted by carving from the wood material grown over individual years. The samples are processed to cellulose and the cellulose into pure carbon by burning and chemical reduction. The fraction of radiocarbon in pure carbon is measured using a particle accelerator. "Radiocarbon is like a cosmic marker describing phenomena associated with Earth, the solar system and outer space," says Markku Oinonen, Director of the University of Helsinki's Laboratory of Chronology, who headed the study. Mapping solar storms A solar storms corresponding to the Carrington event in modern times would disrupt electrical and mobile networks and cause major problems for satellite and navigation systems, leading to problems in, for example, air traffic. This is why accurate knowledge of solar behaviour benefits society. Solar storms smaller and more common than the Carrington storms can be studied with measuring devices and satellites nowadays, while larger ones can be investigated, for example, by measuring radiocarbon concentration in tree rings. So far, it has not been possible to study specifically medium-sized storms such as the Carrington event, which have not occurred in modern times, using conventional radiocarbon techniques. This recent study opens up a potential new way of investigating the frequency of Carrington-sized storms, which may help to better prepare for future threats. Increasingly accurate information on the carbon cycle The results were interpreted using a numerical model of radiocarbon production and transport developed by researchers at the University of Oulu. "The dynamic atmospheric carbon transport model was specifically developed for describing geographical differences in the distribution of radiocarbon in the atmosphere," says Postdoctoral Researcher Kseniia Golubenko from the University of Oulu. What was significant in the recently published study was how the radiocarbon content of trees in Lapland differed from that of trees at lower latitudes. The first measurements were carried out at the Accelerator Laboratory of the University of Helsinki, while repeat measurements conducted in two other laboratories significantly reduced the previous uncertainties. The discovery can help to better understand atmospheric dynamics and the carbon cycle from the time before human-generated fossil fuel emissions, enabling the development of increasingly detailed carbon cycle models. "It's possible that the excess of radiocarbon caused by the solar flare was primarily transported to the lower atmosphere through northern regions, contrary to the general understanding of its movement," muses Doctoral Researcher Joonas Uusitalo from the Laboratory of Chronology. Other sources of radiocarbon "It's also possible that the cyclic change in the production of radiocarbon in the upper atmosphere caused by the variation in solar activity has resulted in the local differences on the ground level seen in our findings," Uusitalo adds. According to Uusitalo, the dominant fraction of radiocarbon is produced by galactic cosmic rays coming from outside the solar system, even though exceptionally strong solar storms generate individual bursts of the isotope in the atmosphere. Cosmic rays, in turn, are weakened by solar wind, a continuous flux of particles originating in the Sun that fluctuates between stronger and weaker in 11-year cycles. The topic requires further research. Historical records show that significant geomagnetic storms also took place in 1730 and 1770, which is why their tracking is likely to be in focus next. The recently published study was carried out as a collaborative project of the University of Helsinki's Laboratory of Chronology and Department of Physics, and Natural Resources Institute Finland. Researchers from the University of Oulu, Nagoya University, Yamagata University and ETH Zurich also contributed to the study. The study received funding from the Research Council of Finland, the Finnish Cultural Foundation and the Emil Aaltonen Foundation.