Under the weather?

Tuesday, July 03, 2007

Roger Dobson

Thunderstorms

Asthma, headaches, migraine, allergies, mood

Asthma rates can sore within 60 minutes of a thunderstorm. Research at Imperial College into the effects of one storm in London shows: “A sudden and extensive epidemic occurred within about an hour, affecting possibly several thousand patients.” Most of these people were found to have antibodies to grass pollen, but the researchers were unable to conclude exactly how storms increase asthma attacks. A second study suggests that pollen grains are ruptured by the thunderstorm, releasing large amounts of concentrated inhalable allergens.

Humidity

Headaches, migraine, ear wax, sickle-cell anaemia, insomnia, gout, respiratory viruses, rheumatoid arthritis

More than half of headaches are triggered by weather, say researchers at the Children’s Hospital, Boston. In their study group, one in three headaches were caused by changes in humidity and temperature, while 13 per cent developed as a result of changes in barometric pressure. A study at Kingston University, Surrey, shows that painful sickle-cell anaemia symptoms increase when humidity is low and wind-speeds are high, as a result of the weather conditions cooling skin.

Research at Nahdha Hospital in Oman shows that people living in areas with high humidity are twice as likely to have problems with ear wax, while work in Boston shows attacks of gout are more frequent on days of high humidity, possibly because of the effects of dehydration. A study at the State University of New York suggests that respiratory viruses are most active when humidity is high.

Barometric pressure

Arthritis, headaches, births, pain, memory, violence, mental health, behavioural problems

Researchers have found that slight low-frequency atmospheric pressure can influence human mental activity, causing significant changes in attention span and short-term memory functions. It’s long been claimed that osteoarthritis symptoms worsen with the weather, and research at Tufts University in Boston shows this may be linked to both barometric pressure and temperature. And a study at Tokyo Medical University shows that deliveries increase when atmospheric pressure falls, possibly as a result of early breaking of the foetal membranes.

Elsewhere, researchers at the University of Louisville School of Medicine found that acts of violence and emergency psychiatry visits are also linked, while a study of rheumatoid arthritis patients in Spain shows that low pressure and low temperature both increase joint pain. Russian scientists have also reported that low atmospheric pressure can slow mental activity.

Sun

Cancer, seasonal affective disorder, pain, fertility, diabetes, heart disease, high blood pressure, multiple sclerosis, psoriasis

Sun exposure may increase survival chances for cancer patients. Research shows that women diagnosed with breast cancer in the summer have a 14 per cent higher chance of survival than those diagnosed in the winter, while men and women found to have lung cancer in thesummer had a five per cent lower risk of dying.Sunlight is essential for the production of vitamin D in the body, and one explanation could be that this vitaminhelps stop the growth of tumours. “We found substantial seasonality in cancer survival, with diagnosis in the summer and autumn months being associated with improved survival, especially in lungand breast cancer patients,’’ say researchers from King's College. Meanwhile, scientists at the Naval Health Research Center in San Diego found that the right levels of vitamin D halve the risk of colon cancer, and doctors at the University of Milan found that patients admitted with clinical depression who were allocated hospitals beds with high levels of sunlight in the mornings went home 3.67 days earlier than average.

Rain

Mood, plague, water-borne infections, headaches, respiratory problems

Research at the University of New Mexico shows that cases of plague in humans occurred more frequently in years when rainfall was 13 per cent above normal. Their conclusion is that the moist environment means more disease-carrying fleas survive and reproduce. A study at Trinity College, Dublin, shows that rainfall has an effect on mood and on the buying of stocks and shares, while researchers at Canada’s University of Guelph have found that water-borne infections including E. coli, increase after heavy rainfall. High rates of dampness have been linked to headache and respiratory problems, while levels of negative ions the air after a storm may also affect mood.

Cold

Heart disease, Raynaud’s phenomenon, depression, stroke, low birth weight, knee pain, Bell’s Palsy

Reports from a number of centres, including Boston University, have found links between cold weather and an increased risk of cardio-esvascular disease. One of the theorie is that blood moves more slowly in colder temperatures and is therefore more prone to clotting, especially in arteries already narrowed by disease. A study at Uppsala University Sweden, shows that cold summer days have an effect on health, too, with antidepressant use increaseing significantly on colder days in the summer months. A report from the US National Institutes of Health shows that summer babies tend to be of lower weight, probably because of the effects of cold temperatures in the early stages of the pregnancy. And researchers at La Paz Hospital in Madrid found the nuumbers of cases of Bell‘s Palsy rose in colder weather.

Heat

Premature death, dehydration, crime, respiratory disorders

Just like excessive cold, too much heeat can also cause a premature death. A study at Fudan University, Shanghai, found that a 1C rise in average temperature over three days led to a 37 per cent increase in mortality rates, a con-clusion borne out by the higher death rates across Europe during the heatwave of 2003. The Italian National Institute of Health saw expected mortality rates rise by 15per cent, while in the UK, it's estimated that there were 619 more deaths than usual during that 31-day heatwave period. There is also an increased risk of bad behaviour and rioting with temperature. According to a Manureschester University report, temperatue of 27, 29, and 34 degrees have all been identified as “riot temperatures”.

Wind

Mood, headaches, depression, flu, hot flushes, sickle-cell anaemia, insomnia

Studies in Austria show that high winds lead to a 20 per cent rise in suicides. More than one in three people surveyed by Germany's Allensbach Institute said wind affected their health. One theory is that the changes are as a result of electrically charged air. Negatively charged air has been shown to improve mood – warm winds are more positively charged.

Blue skies

Can have a big impact on mood

“When the skies were blue, general self-esteem and aspects of confidence are higher and people have a more daring and adventurous attitude towards the day ahead,” says Geoffrey Beattie, Head of Psychological Sciences at Manchester University.

Mist

Fine mist has also be shown to increase rates of asthma attack, according to research at Japan’s Kanaya Paediatric Clinic. There, scientists found that mist triggered 70.7 per cent of attacks.

Clouds

Clouds have an effect on mood, and can seriously affect the chances of being accepted for university. According to research, academics who make admissions decisions are heavily influenced by the state of the weather on the day they consider applications. Researchers found that change in cloud cover can increase a candidate’s chances of admissions by 11.9 per cent. Academics were found to give more weight to academic achievements on cloudy days, and greater weight to social activities on sunny days, according to a report in the Journal of Behavioural Decision Making.

Pollen

High pollen counts in spring may trigger seasonal depression, according to a study at the University of Maryland. Researchers say that pollen results in inflammation of the airways, and that the same inflammation triggers depression in vulnerable people.