MS risk is shaped by geography, not just genes

Lack of Vitamin D seems to be one major factor fueling MS risk

Researchers believe that a combination of factors can elevate MS risk, including a lack of vitamin D exposure in different locales, genetic history, cigarette smoke exposure, and Epstein-Barr virus infection.

See MS prevalence by region in the United States

This map underscores that people in the northeastern United States have more cases of the disease as compared to the south, west, and midwest. On an individual level, these numbers may still differ based on genetic makeup and other factors irrespective of where people live.

Winter-risk SAD is more likely in regions above 40 degrees latitude north

Using latitude, depression prevalence, and populations of women and those aged 18-30, this map shows the risk of experiencing seasonal affective disorder during the winter. Researchers weighted latitude most (50%) and demographics least (5% each for women and young adults). Overall risk is not a useful predictor of prognosis for an individual.

MS can damage the brain up to 7 years before symptoms appear

Recent research scouring blood samples from 134 people with MS, both before and after their diagnosis, found that about seven years before these patients were diagnosed, there was a spike in a protein called myelin oligodendrocyte glycoprotein—indicating disease-associated damage to the protective myelin around nerve fibers.

MS Drugs reduce inflammation, helping reduce relapses and slow disease progression

Disease-Modifying Drugs calm the body's inflammatory response to help stave off relapses—when new or existing MS symptoms show up for a day or longer. Avoiding smoking, exercising, reducing stress via mindfulness, checking for vitamin D deficiencies, drinking more water and eating well, all can slow disease progression. [The jury's still out on if HRT around the time of menopause may reduce dementia risk](https://www.thelancet.com/journals/lanhl/article/PIIS2666-7568(25)00122-9/fulltext) Estrogen can reduce inflammation and support neural growth in the brain, and some research has suggested that beginning hormone replacement therapy around menopause—versus later in life—reduces Alzheimer's disease risk. Still, a recent systematic review concluded that taking HRT didn't affect dementia risk, regardless of when women started taking it, so the science remains unsettled.

Even if you have some ASD-linked gene variations you may not develop ASD

Individual environment and life experiences affect how genes perform in the body, potentially adding methyl groups to DNA that affect their function and turning genes on and off—which may heighten or reduce disease risk.

Caucasians are at the greatest risk of developing macular degeneration

A 2016 analysis across ethnic groups found, among other things, that white participants had the highest incidence of the disease, followed by Chinese, Hispanic, and Black participants. This study did not answer why that may be the case.

Females are diagnosed with MS roughly 3 to 4 times more often than males

This PBS documentary traces a filmmaker's personal journey with MS after being diagnosed at age 26. It encompasses both his efforts to stymie the disease's progression and his search for answers about the disease, when, statistically, he seemed at low risk due to his gender, lack of known family risk, and other factors.

Stroke risk doubles each decade after age 55

While age is the greatest risk factor, genetics, diet, and overall health play a prominent role in determining individual stroke risk. Prevention focuses heavily on modifiable risk factors. High blood pressure is the single most important controllable risk factor, contributing to both types of stroke.

Twin studies helped scientists understand why mosquitoes like some of us more than others

A combination of carbon dioxide output, skin chemistry, genetic factors, hormones, and clothing choice can make us particularly vulnerable to mosquito bites. Watch how mosquitoes responded to one man in the video versus his wife, a research approach typically conducted with identical and fraternal twins to test mosquito attractiveness.

Climate determinism wrongly linked human traits and societal progress to geography

Historically rooted in Greek philosophy, its ideas used the latitudes where people were located to justify racial hierarchies, casting tropical peoples as lazy or inferior. These biases still influence how media and research portray people in climatically disadvantaged regions. (Some readers may experience a paywall.)

Environmental conditions, shifting immunity, and viral strain could help explain 2025 spike

The surge in HFMD in the summer and early fall of 2025 in the mid-Atlantic could be the result of a confluence of factors, including a more virulent strain of disease-causing virus, good environmental conditions for the virus to spread—hot, humd—and a potential immunity gap among kids due to milder HFMD outbreaks the previous year.

Multiple sclerosis means 'many scars'

That's a reference to the scarring or lesions that occur in the brain, spinal cord, and elsewhere whenever the immune system has a flare-up. The immune system attacks the myelin because it incorrectly responds as if it's a threat, damaging the body's ability to transmit electrical signals effectively from areas of the body to the brain.

Learn how your earwax may be determined by genetics—and geography

Researchers have discovered that wet and dry earwax are associated with specific gene variations. Wet earwax is particularly associated with warmer areas of Europe, Asia, and the Americas, suggesting that dry earwax may have been evolutionarily advantageous in cooler climates.

Some data links schizophrenia to older paternal age and birth complications

Yet both associations are not yet considered firm enough to definitively be causative. Schizophrenia is a multi-causal syndrome and a mixture of factors, including genetics, are widely believed to be behind its development.

Cancer rates are on the rise among GenXers and Millennials

Cancer rates are rising among Gen X and Millennials, with more cancer diagnoses being made in their 30s and 40s than previous generations. Factors such as prenatal exposures, environmental toxins, and lifestyle choices may contribute to this trend. Memorial Sloan Kettering Cancer Center's experts discuss these issues, exploring how these insights could reshape cancer risk understanding.

How the gut microbiome can affect heatstroke risk

Some research suggests that our gut microbiome influences our risk of exertional heatstroke. If exercise boosts our body temperatures to unsafe levels, increasing gut permeability, that can cause a "leaky" gut—allowing bacteria and other gut microbes to leak into the bloodstream and potentially trigger endotoxemia, a potentially life-threatening inflammatory response that can occur with heat exhaustion and heatstroke.

Microgravity can alter the evolution of viruses and bacteria

Experiments conducted on the International Space Station have shown that microgravity environments can delay viral and bacterial infections and induce mutations not seen on Earth. These mutations could have implications for long-term space missions and human health and suggest space can serve as a testing ground for developing new therapeutic approaches.

Antimalarials must be taken before traveling to a malaria-endemic area

Malaria prevention involves avoiding getting bitten by mosquitoes (with bug spray and clothing choices) and taking malaria preventative drugs before, during, and after spending time in an area with malaria risk. The drug must be in the blood before the traveler is exposed to malaria parasites.

Between 2006 and 2021, 444 people died from lightning strikes in the US

The National Oceanic and Atmospheric Administration reports that the odds of being struck by lightning in one's lifetime are one in 18,864. Participation in outdoor activities during the summer months in Florida, Texas, and Colorado increases one's risk of exposure.

Measles evolved from an ancient cattle disease as early as 3,000 years ago

Genetic analysis suggests that the closest modern relative of measles is a livestock virus known as rinderpest, with the viral strains diverging between 2,000 and 3,000 years ago. The timing coincided with the rise of major cities above 250,000 people, offering a novel transmission route for the newly mutated measles virus.

Most adults don't need a daily vitamin, and it won't extend your life

A 20-year study by the National Cancer Institute involving almost 400,000 people found that daily multivitamins did not help people live longer. In some cases, these vitamins also increased the risk of death. Although some subpopulations—such as those with documented vitamin deficiencies and pregnant individuals—should take vitamins, daily multivitamins should not be taken uniformly by adults. Instead, patients should discuss vitamins with their clinicians and consider baseline vitamin testing before starting vitamin regimens.

Migrane 101: data, symptoms, and treatments

Living with migraine, however often the neurological condition attacks, is a journey fraught with pain and isolation. This migraine guide offers insight into the condition, common triggers, possible treatments, personal stories, and tips for managing life with migraine.

Blue zones are regions with unusually high numbers of centenarians

Factors thought to contribute to longevity in these regions include diet and social connections, but their legitimacy is often questioned due to a lack of rigorous scientific methodology and potential record inaccuracies.

What the research says about the link between lead pollution and crime

The lead-crime hypothesis links childhood lead exposure to impulsivity and aggression as an adult, traits typically associated with higher crime risk. A 2022 meta-analysis found that reducing lead may explain up to 28% of the US homicide decline, but not the broader crime drop.

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

Poison ivy will likely become both larger and more resilient due to climate change.

Astronauts have repaired genetic damage in space using CRISPR—a molecular tool that can make precise changes to DNA and is used in single-celled organisms to attack invasive viruses.

Louisiana's 'Cancer Alley' is infamous for having some of the highest industrial pollution, toxic air emissions, and cancer risks in the US.

Human-to-human transmission of hantavirus remains extremely rare, so the 2026 hantavirus cruise ship outbreak doesn't mean we're facing a COVID-style pandemic risk.

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

About 12.5% of US adults experience a phobia in their lifetime, a diagnosis that hinges on the intense fear interfering with daily life and persisting for at least six months.

While El Niño moves warm Pacific Ocean waters east along the equator, La Niña moves them west, shifting where rainfall will become more common for months.

Listen to an in-depth conversation on the links between Parkinson's disease and herbicide exposure and the challenging pace of scientific investigation.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

Visualize the path of every solar eclipse from 1900 to 2099 and see what each looks like when observed from different locations on Earth.

Tattoos remain visible on your skin thanks to immune cells called macrophages

Telehealth demand for GLP-1s for weight loss is booming as consumers seek easier access.

In 2026, Finland was named the world's happiest country for the ninth consecutive year based on its wealth, social safety network, and high life expectancy, among other factors.

Dirty lightning is a thunderstorm created from friction between rising and falling flows of ash and smoke during volcanic eruptions.

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

In 2018, 26-year-old missionary John Allen Chau was killed by tribesmen after attempting to reach and evangelize on India's isolated North Sentinel Island

The word 'jazz' evolved from 'jasm,' 19th-century American slang for 'energy'

In 1939, baseball star Lou Gehrig delivered his inspirational 'Luckiest Man' speech after retiring due to the health condition that now bears his name.

Use this tool to calculate the dollar value of your parental mental load, from meal planning to coordinating after-school care, then see resources that help generate solutions.

In 2019, a laptop loaded with six of the worst malware in history and described as 'an exhibit of historical weaponry' sold for $1.3M.

The Russia-Ukraine conflict is the largest ground war in Europe since World War II in terms of casualties, forces mobilized, and displacement of civilians.

The US Constitution is widely regarded as the longest-standing written national constitution still in force—see how it has influenced rights worldwide.