Healthy News for Healthy Nation

A research on the bone health of one of the oldest persons in the world raises the question of which has the most effect on the human lifespan: genetics or a healthy lifestyle or some combination of the two? Research reveals that there were no genetic modifications which could have contributed to the longevity of a 114-year old Spaniard. The research team, directed by Universitat Autònoma de Barcelona professor Adolfo Díez Pérez, pointed out a healthy lifestyle, a Mediterranean diet, a temperate climate and daily cycling until the age of 102 as the reasons for his excellent health.

The research team studied the bone mass and analysed the genetics of a man with enviable health who at the time of the study was 113 years old. The research was carried out with four other members of his family: a 101-year-old brother, two daughters aged 81 and 77, and a nephew aged 85, all of them born and still living in a small town of the island of Menorca. The research findings reported that the man’s bones were in excellent conditions: his bone mass was normal, there were no anomalous curvatures and he had never sustained a fracture.

With regard to the genetical analysis, researchers were unsuccessful in finding any mutations in the KLOTHO gene, which is generally related to a good level of mineral density and therefore healthy bones. Neither did they find any mutations in the LRP5 gene, which is associated with longevity. None of the members of the family who participated in the study presented any mutations in this gene.

The results of the research do not rule out the possibility that other genetic mutations could positively influence longevity. However, researchers do point out the fact that the excellent health of this family, and of the 113-year-old man in particular, is probably due to a Mediterranean diet, the temperate climate of the island, a lack of stress and regular physical activity. The article underlines the fact that until the age of 102, the man cycled every day and looked after the family orchard.

The human life-span and the nature vs nurture question raises the question of why do animals age so differently? Why is it that a tortoise, for example, can live well over a hundred years, while another similarly sized animal would be lucky to live just 10? What’s the big difference?

Scientists say that the secret lies in genetic expression. A new genetic database could help reveal how and why animals age so differently. The process of mapping out this molecular maze will likely unlock some of the hidden secrets of increased longevity in humans along the way.

In some instances, even very closely related animals have drastically different life spans, a fact that has puzzled scientists for years. Mice for example live for about two years while their rodent cousins, the Southern flying squirrel, can live for two decades or so. Chimps and humans are 99 percent genetically identical, so why do humans live twice as long? New databases are helping to identify the genetic expressions that accounts for these vastly varying life spans.

In a study of mice, researchers at Stanford University and the National Institute on Aging (NIA), have now generated a database that catalogues how gene expression, the measure for how active a gene is, changes in various parts of the body as the animal ages. Their findings indicate that different tissues age quite differently over time.

Previous studies have examined how gene expression changes with age in specific parts of the body, such as the brain or the hearts of both mice and humans. But the new study, commissioned by the NIA, simultaneously analyzed the activity of thousands of genes in 16 different tissues at different points during the animals’ lives. This has allowed researchers to compare age-related patterns of gene expression between different organs.

The results, published earlier this week in the journal PLoS Genetics, established that the two main culprits previously believed to be primary contributors to the aging process—increased inflammation and slowed metabolism—are indeed guilty parties. But the researchers did find large disparities depending on the different tissues of the body. For example, expression profiles in the liver, brain, and muscle changed little with age, whereas the lungs, eyes, and thymus (an immune organ) experienced more radical transformations.

The researchers compared their results with other previous studies analyzing gene-expression. They analyzed the aging brain, muscle, and kidney tissue in humans, flies, and worms. The researchers found one central theme to gene expression and aging in all four species. They all developed a slowing of the cells’ energy factories. In each species, expression of genes related to energy production dropped twofold by the time the species reached the end of its life span—2 years for mice and around 80 for humans.

“This is the only common property of growing old between the four different animals,” says Stanford biologist, Stuart Kim. “Maybe that should alert us to say there is something unavoidable to getting old.”

However, the researchers said there were not a lot of universal similarities, which raises the question of how well lab animals can really serve as models for humans as we attempt to unravel the longevity mystery. For example, studies have found that in humans, and some other animals, that the length of repetitive strips of DNA at the end of each chromosome, also known as telomeres, is linked to aging. However, the researchers didn’t find changes in the expression of telomere-related genes in aging mice.

“I wouldn’t say that this means that model organisms can’t be used to study aging in humans,” says Promislow. “It does suggest there is a lot more going on.”

This analysis will likely be the first of many to come that will take advantage of this new database, know as AGEMAP. Scientists are still working on figuring out the precise functions of the intertwining genetic networks implicated in aging. AGEMAP serves as a way to decipher differences in genetic expression and better map out the ageing process, especially as it relates to humans.

“The scale of this study is phenomenal,” says Promislow. “In some ways, this shows us where things are likely to be headed in coming years in terms of the kinds of experiments people will do to understand the genetic basis of complex traits.”

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Tea, vegetables and even cheese and chocolate (woo hoo!) can help

There are visible signs of the consequences of global warming everywhere you look—ice caps melting, weather patterns becoming increasingly erratic, and animals migrating because of climate changes. One slightly less visible, though just as nerve-wracking, sign is in the form of an annoying little mosquito buzzing around your ear.

Mosquitoes and other insects have long been harbingers of disease, but global warming is allowing them to venture into the newly warmer areas and spread once uncommon ailments to unfamiliar locations. The following are five diseases that, much like Al Gore’s career, have had a comeback thanks to global warming.

Dengue Fever
The Aedes mosquito, which transmits the dengue fever virus, lives primarily in tropical and subtropical climates. Frost kills mosquito larvae and adults, effectively limiting the temperature range in which it can survive. However, with warming temperatures, the mosquitoes and the disease have expanded their range.

Aedes has been detected as far north as the Netherlands. In 1995, a town in Texas experienced a small outbreak of dengue. Chikungunya, a disease with symptoms similar to dengue and carried by Aedes mosquitoes, recently caused a 300-person outbreak in a small town in Italy. According to the World Health Organization (WHO), this is the first time a disease only seen in the tropics was found in modern Europe.

As higher altitudes become warmer, the dengue-carrying mosquito is also moving to higher ground. Normally limited to elevations of 3,300 feet, in the past three decades, the mosquito has been found at 5,600 feet in Mexico and at 7,260 feet in the Andes.

Since mosquitoes thrive in stagnant water, rainstorms and flooding, induced by climate change, have caused epidemics of mosquito and water-borne diseases. When three feet of rain fell on Mumbai in one day in 2005, the flooding caused epidemics of dengue fever and malaria, as well as cholera.

Malaria
As is the case for dengue and chikungunya, rising temperatures have expanded the range of the Anopheles mosquito that carries malaria. Malaria is now found in highland regions in Africa, where it had previously not been detected; a WHO report found that warming caused malaria outbreaks in Rwanda and Tanzania and caused the disease to expand its range in Kenya. According to a report issued by the Harvard Medical School, malaria is not only circulating at higher altitudes; it is also maturing at a faster rate. At 68° F, the malarial protozoa take twenty-six days to incubate; at 77° F, they take half that time. Since Anopheles live only several weeks, warmer temperatures mean greater replication and transmission of the parasite.

Up until recently, the United States had completely eradicated malaria, but the Anopheles mosquitoes are present in the U.S. Small outbreaks of locally transmitted malaria have occurred in the past decade in Texas, Georgia, Florida, Michigan, New Jersey, and New York.

West Nile
West Nile Virus had never been documented in the Western Hemisphere until 1999, when it was determined by the Centers for Disease Control to be the cause of an encephalitis outbreak in New York. How WNV appeared in the U.S. is unknown, but extreme weather conditions can amplify virus replication in animals and birds. Drought followed by warm temperatures is a particularly favorable and common condition for outbreaks.

In 1999, a severe drought followed by a mild winter may have set the stage for WNV outbreaks. In the summer of 2002, drought and hot weather caused WNV to spread across the U.S. and into Canada, killing 304 people in North America.

Rift Valley Fever
While the mosquito that transmits West Nile can thrive in small pools of water left after drought, uncharacteristically wet weather can lead to outbreaks of Rift Valley Fever, an emerging pathogen whose rise has been attributed to changing global weather patterns. Recently, both Kenya and Madagascar have experienced outbreaks following severe rainstorms and flooding. The mosquito population, whose eggs can survive for years in dry weather and hatch to produce infected larvae in wet weather, spreads the virus to livestock, which then spreads it to humans.

If global warming continues unabated, weather patterns will become more erratic, bringing stronger storms and floods, creating ideal breeding grounds for the Rift Valley fever virus.

Lyme Disease
Warmer weather is contributing to a rise in Lyme disease in two ways: higher temperatures allow both ticks to thrive and people to stay outdoors more. A study conducted by the Center for Health and the Global Environment at Harvard Medical School found that rising temperatures during winters in North America are causing a growth in tick populations, which has led to more Lyme disease cases. Like mosquitoes, ticks are attracted to warmer conditions, so as climate change gradually increases the temperature in northern geographic areas, ticks will find new homes (and new targets).

These diseases aren’t just due to climate change—globalization, loss of predators, ecological factors, and lack of prevention play a role. But their increasing incidence and range, due in large part to warmer weather and extreme rainfall, make them seem like the canaries in our global coalmine.

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What makes for a stressful day?

It’s widely thought that employees on lower grades suffer if they have little control over their jobs. Is this true?

A group of middle managers gathers in central London for a half-day workshop on stress. Merren Barber, an occupational health physiotherapist, delivers a stark warning: managers who put too much pressure on their workers can cause serious health problems.

“Stress isn’t an illness but there’s quite a bit of evidence that it increases the risk of high blood pressure, heart disease and mental health problems. So people potentially can become ill because of chronic stress,” Barber tells the group.

Is this really true?

Stress management courses are now a staple of corporate life and the claim often made that there is a link between stress and ill health has become the received wisdom.

The Health and Safety Executive (HSE), the government body in charge of protecting people’s health at work, has even made giving workers more control over their workload a legal obligation.

According to employment lawyer Gordon Turner, the HSE standards on stress are so rigorous that many employers fear details of their working practices becoming public. “It’s so easy to slip up. If an employee takes a grievance as far as an employment tribunal, companies often settle rather than risk a public hearing that might attract the attention of the HSE.”

Both the HSE and stress management trainers are influenced by a famous survey of the health of British civil servants known as the Whitehall II study. Led by Prof Sir Michael Marmot, an epidemiologist at University College London, Whitehall II has tracked the lives of thousands of civil servants for more than 20 years in an attempt to assess the effect of job status on health.

According to Professor Marmot, it is not stress per se that has an adverse effect on health and life expectancy. Rather it is working in a job where there are high demands accompanied by a lack of control. “People of high status tend to have high demand and that doesn’t seem to cause any illness problems at all.”

Is it working closely with the boss…

Some academics in this field have their doubts. Dr John MacLeod is one of a team of researchers at Bristol University who are sceptical about Professor Marmot’s findings.

“We looked at these issues in a study of 6,000 working men in South West Scotland. Unusually, when these men were recruited in the early 1970s, it was the middle classes and the more advantaged who were experiencing high levels of stress. In those circumstances stress was not associated with poorer health.”

Professor Marmot’s response is that the Scottish study does not use good measures of stress.

Sick of work

As far as heart disease is concerned, it is not only Dr MacLeod and colleagues at Bristol University who are unconvinced there is a proven link with stress. The American Heart Association website states that “current data don’t yet support specific recommendations about stress reduction as a proven therapy for cardiovascular disease”.

… or not closely enough?

Dr MacLeod believes that so-called psychosocial explanations of ill health are a distraction from what he believes are more likely causes of a growing health divide between richer and poorer people.

“We don’t really know the causes but material disadvantage in childhood is one of the strongest predictors of health in adulthood. So the best bet would be to target and reduce childhood deprivation if we want to see reductions in health inequalities.”

So are companies wasting money by sending managers on courses that might make them feel guilty about placing high demands on their workers?

Dr MacLeod doesn’t go that far. “It may not reduce the risk of heart disease but creating fairer workplaces is a humane and just thing to do.”

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