Monday, December 21, 2009

Where the Action Is: On the Site of the "Playful" Life (Part 5: Children at Play)

Lately I haven't been able to keep up with my series of posts on play. Teaching a new course both this and next term, coupled with taking on some new administrative responsibilities, and polishing some other pieces of work, all necessitated putting my research on play on the back burner for a few months.

So as a treat to myself I have put aside some time over the holiday break to read this book, entitled Children at Play. Like aging, I believe play is among one of the most important neglected issues of our times.

What I intend to with my blog is make a note of some important parts of Chudacoff's (CH) book so I can easily refer back to them in the future. So below are my notes on the first 50 pages of the book.

The book will focus on children between the ages of 6-12. And in the intro CH notes Mark Twain's definition of play: "Work consists of whatever a body is obliged to do. Play consists of whatever a body is not obliged to do" (1). CH notes that it is almost impossible to provide a single, acceptable definition of play.

For Twain's character Tom Sawyer (pictured above), play is, notes CH, spontaneous, joyous activity. But CH notes that play experts also emphasize the functional, utilitarian qualities of play. Play helps an individual acquire vital social, emotional, physical and cognitive skills (1).

The psychologist Garvey identifies 4 components of children's play: (1) it is pleasurable; (2) play has no extrinsic value; (3) play is freely chosen; and (4) play involves active engagement on the part of the player (3).

And CH considers 4 components of play: (a) the environment (setting where play occurs), (b) the materials, (c) dramatis personae, and (d) freedom (how much control a child has over the activity.

Chapter 1 of the book considers play in America from 1600-1800. CH distinguishes between different racial groups- whites, African and Indian peoples- as well as boys and girls. Most play during the colonial era took place outdoors. Only a small minority of the population lived in cities.

Ch summarizes the situation of preadolescence children during this era as follows:

...While Indians, African Americans and whites made important contributions to the family economy, they were at times able to build their own play culture, more alternative than oppositional, around a mostly unstructured kind of play. Whether roaming through woods and interacting with nature along the way, or creating fantasies and games with self-fashioned playthings, or simply socializing with siblings and, when available, other children, young people in their preteen years manifested a definite play instinct. This is not to deny that challenges and hardhsip filled their lives; they toiled in fields and households, they fought illness and sorrow, they endured dry summers and harsh winters, and they struggled with warnings of dire consequences for defying parents and God. Still, they tried, and sometimes succeeded, to follow their own "inclinations" (38).

That's all for now in terms of a few notes from the Intro and Ch. 1. I hope to do another post or two on the rest of the book over the holiday period.


Sunday, December 20, 2009

Science Breakthrough of 2009

The journal Science has chosen the discovery of "Ardi", a 4.4-million-year-old skeleton pictured here, as the breakthrough of the year.

A sample of the News piece on Ardi:

...a 4.4-million-year-old female who shines bright new light on an obscure time in our past. Her discoverers named her species Ardipithecus ramidus, from the Afar words for "root" and "ground," to describe a ground-living ape near the root of the human family tree. Although some hominins are even older, Ardi is by far the most complete specimen of such antiquity. The 125 pieces of her skeleton include most of the skull and teeth, as well as the pelvis, hands, arms, legs, and feet.

....In the year of the bicentennial of Darwin's birth, it seems fitting that researchers finally broke through the 4-million-year barrier to understanding our origins. Models for our earliest ancestors can now be informed by plenty of fresh data and at least one body of hard evidence.

And you can watch the video here.

Among the "runners up" this year includes my favourite-- the discovery that the drug rapamycin increases life span. An excerpt from the story on rapamycin:

Doctors prescribe rapamycin to battle kidney cancer and to stymie rejection of transplanted organs. After the U.S. National Institute on Aging added the drug to its list of molecules that might increase rodent life span, the three U.S. labs that test such candidates started feeding rapamycin to mice when they were 600 days old, comparable to 60-year-old people. The rapamycin-rich diet added between 9% and 14% to the rodents' life span. Researchers had achieved similar feats in worms and flies, but the result was a first in mammals—and especially encouraging because the animals were already past their prime.

The drug's mechanism has scientists puzzled. Rapamycin curbs the TOR biochemical pathway, which is involved in everything from protein synthesis to cell division. However, the drug didn't thwart any specific cause of death: The mice suffered the full range of old-age infirmities such as ulcers and heart failure. And because the mice didn't become skinny, the researchers doubt that rapamycin works similarly to calorie restriction (CR)—an extreme diet that can increase longevity in mice and some other lab organisms—although other scientists think there might be a connection.


Friday, December 18, 2009

PNAS Study on Naked Mole Rat's Resistance to Cancer

This picture is of the naked mole rat, the world's longest living rodent. They have a maximum lifespan of 28 years. Unlike regular mice, which are highly prone to cancer, the mole rat seems to be immune to cancer. So understanding how these mammals can live so long could help us improve the health opportunities of humans.

The latest issue of the PNAS has this study on the cancer resistance of the mole rat. Here is the abstract:

The naked mole-rat is the longest living rodent with a maximum lifespan exceeding 28 years. In addition to its longevity, naked mole-rats have an extraordinary resistance to cancer as tumors have never been observed in these rodents. Furthermore, we show that a combination of activated Ras and SV40 LT fails to induce robust anchorage-independent growth in naked mole-rat cells, while it readily transforms mouse fibroblasts. The mechanisms responsible for the cancer resistance of naked mole-rats were unknown. Here we show that naked mole-rat fibroblasts display hypersensitivity to contact inhibition, a phenomenon we termed “early contact inhibition.” Contact inhibition is a key anticancer mechanism that arrests cell division when cells reach a high density. In cell culture, naked mole-rat fibroblasts arrest at a much lower density than those from a mouse. We demonstrate that early contact inhibition requires the activity of p53 and pRb tumor suppressor pathways. Inactivation of both p53 and pRb attenuates early contact inhibition. Contact inhibition in human and mouse is triggered by the induction of p27Kip1. In contrast, early contact inhibition in naked mole-rat is associated with the induction of p16Ink4a. Furthermore, we show that the roles of p16Ink4a and p27Kip1 in the control of contact inhibition became temporally separated in this species: the early contact inhibition is controlled by p16Ink4a, and regular contact inhibition is controlled by p27Kip1. We propose that the additional layer of protection conferred by two-tiered contact inhibition contributes to the remarkable tumor resistance of the naked mole-rat.

And the NY Times has the scoop on this study here.


Thursday, December 17, 2009

Nature Editorial on Narrowing the Gap Between the Natural and Social Sciences

This editorial in the latest issue of Nature is an interesting one on the gulf between the natural and social sciences. A sample:

The relationship between the social sciences and the natural sciences has historically been fraught. 'Hard' scientists have often treated the social sciences with disdain. For example, some of them fought, successfully at first, to exclude the social sciences from the remit of the US National Science Foundation. And those social scientists who studied science itself, under the remit of science and technology studies, often returned the favour, seeming on occasion to be devoting themselves myopically to demonstrating that the scientific emperor had few, if any, clothes.

There remains something of a dialogue of the deaf between these two wings of the academy, separated as they are by language, custom and methodology. But barriers are coming down. Senior scientists and administrators, especially those in socially contentious areas such as climate change and reproductive technologies, realize that they need to collaborate with scholars of society-at-large. Sociologists and philosophers of science, in turn, are acquiring a more intimate understanding of the scientists that they study.

....None of this should encourage a dismissive attitude among sceptics. The applications of genetics, nanotechnology, synthetic biology and other technologies are giving rise to substantial new challenges in professional practice and communication, in ethics, in intellectual property and in many other dimensions beyond the science itself. Objective insights into these dimensions have their own value, and the new collaborations should help. The challenge remains to identify how that value can best be fulfilled.

This editorial resonates with me as I attempt to help bridge the divide between political theory and the biological sciences.


Thursday, December 10, 2009

Global Aging: The *Real* Challenge of Our Times

Global aging is real, it's man made, and it threatens the health and economic prospects of the global population, especially the developing world.

Not only is global aging real, it's here now, and its effects are giving rise to a frighteningly new global phenomenon: a pandemic of chronic disease.

(1) Global aging is real.

In 1800, with nearly one billion people alive, life expectancy at birth did not surpass thirty years. By 2000, with more than six billion people alive, life expectancy reached nearly sixty-seven years amidst a continuing rise. (source). In just 200 short years we have more than doubled the average life expectancy that modern humans experienced for tens of thousands of years.

Today there are 600 million people over the age of 60. And by the middle of this century there will be 2 billion people over age 60. (source).

In Canada, for example, the proportion of seniors in the overall population has gone from one in twenty in 1921, to one in eight in 2001. The growth of the seniors population will account for close to half of the growth of the overall Canadian population in the next four decades (source).

Over the past half a century the global distribution of life expectancy has become less skewed. In 1960 the life expectancy of the world's quintile with the lowest life expectancy was 35.9. This had risen to 53 years by 1999, an increase of 48%, and is 80% of the global average. The quintile with the highest life expectancy went from a life expectancy of 70.1 in 1960 to 76.8 by 1999. This was an increase of 10%, and is 16% above the global average life expectancy (source). Despite serious challenges to increases life expectancy (like AIDS in Africa), a demographic convergence is occurring. Population aging is a global, not local, phenomenon.

(2) Aging is "man made"

There are no "aging genes". Unlike vision, dexterity or memory, which are the product of natural selection, aging is the product of evolutionary neglect. Leonard Hayflick describes aging as an artifact of civilization:

Humans are the only species in which a large number of members usually experience aging. Aging in numbers proportional to those seen in humans simply does not occur in feral animals. It occurs only in the animals that humans choose to protect.

....Because humans, unlike feral animals, have learned how to escape the causes of death long after reproductive success, we have revealed a process that, teleologically, was never intended for us to experience. One might conclude, therefore, that aging is an artifact of civilization. (source)

(3) The Moral Duty to Tackle Global Aging

The fact that populations are aging is a mix of good and bad news. On the good news end of things, global aging is an incredible and laudable accomplishment. A number of important advances -- such as technology (especially the sanitation revolution), medical knowledge, material resources, changes in behaviour, etc.- brought a rapid decline in infant, child, maternal and late-life mortality. Humans have never enjoyed the opportunities for health and longevity that they now enjoy.

However, biological aging, and population aging, bring unprecedented challenges. Aging individuals faced increased risks of morbidity and mortality. Chronic diseases like cancer, heart disease, stroke, arthritis, etc. are set to ravage the aging populations of the world. This means unprecedented numbers of humans will suffer years of frailty and disease. Chronic diseases have replaced infectious diseases as the greatest threat to global health. In the year 2005, chronic diseases killed 35 million people worldwide. That number is twice the number of deaths due to infectious diseases (including HIV/AIDS, tuberculosis and malaria), maternal and perinatal conditions, and nutritional deficiencies combined (source).

Aging populations place ever growing stress on health care and pensions.

So the scientific consensus is in: global aging is real. The data is beyond dispute.

And the scientific consensus on the impact senescence has on our health is in-- it increases one's risk of morbidity and mortality. That data is beyond dispute.

So what are we going to do about global aging? At the end of this century our children and grandchildren will look back and ask:

"What were they thinking? Did they not see how dire the consequences of global aging can be? Did they not care about protecting all future generations from the chronic diseases that ravage humans in late life? Did they not care about passing on the economic benefits of the longevity dividend? Why did they focus so much on very low-risk events, like terrorism or catastrophic global warming, and so little on the most likely of risks-- like the chronic diseases of aging?"

(4) What can we do?

Adaptation, Age retardation and Regeneration

Can we just adapt to global aging? No. There are some external modifications we can make to the our environment to promote the health and happiness of aging populations. We can re-design our cities to make them more hospitable to a population with more limited mobility. We can ensure there are public spaces, such as parks, to help promote the fitness of aging populations. We can encourage the population to keep their minds active to help delay the progression of cognitive decline and mental illness, etc.

But adaptation alone will not stop the tsunami of chronic diseases that await the 2 billion seniors that will exist in the year 2050. So what else can we do?

We can search for ways to directly modify our biology to help mitigate the harmful effects of biological aging. If we developed an aging pharmaceutical, for example, that could mimic the effects of calorie restriction we could slow human aging and this would confer health and economic dividends for all future generations to enjoy by increasing the human healthspan and compressing morbidity. We are closer to this than you might think (see this).

And we could also invest in regenerative medicine and develop new interventions that help aging populations enjoy more health and vitality.

We should be bold and imaginative in our deliberations concerning how to meet the challenges of global aging.

But before we can have a serious debate about what to do to address global aging, we must get our heads out of the clouds and acknowledge the reality of what are the most pressing and probable problems that await humanity this century. And global aging should be at the top of that list.


Wednesday, December 09, 2009

Does Parenthood Improve Happiness?

Based on my own personal experience (as a father of three), my answer is a big "YES!".

But what does the scientific evidence suggest? Like most things in life it is a complex issue. I just read this interesting paper in the latest issue of the Journal of Happiness. This study found that having children can increase life satisfaction. Though much depends on how one conceives of "happiness", and factors like a parent's marital status, age, gender, income and education are relevant. Here is a sample from the study:

Surely children involve a lot of work and it is likely that the typical everyday experience with your children is rather negative. But when asked about the most important things in their lives most people would place their children near or even at the top of the list. An ‘‘hedometer’’ might not be able to capture the most rewarding aspects of having children, focusing instead on high-frequency discomforts such as asking teenagers to clean up their room. Measures of life satisfaction, on the other hand, should reflect the low-frequency and more transcendent rewards of having children. A question such as ‘‘How satisfied are you with your life?’’ lead us to take a long-term perspective and consider our personal and professional achievements before answering. Having children can be expected to weight positively in the answer; despite or maybe precisely because of the difficulty of raising them.

....We have found that married individuals in general, and married women in particular, are more satisfied when they have children at home and their satisfaction increases as the number of children in the household increases. We have found that the positive effect of children is present for married individuals of all ages. We have found that rich individuals seem to prefer one child to many, while for most of the population the opposite is true.

....There is thus no denying that children have negative consequences on several wellbeing measures. What we have also found is that despite all these negative sides, when considering their life as a whole married individuals with children report themselves as better off than married individuals without children. The intangible rewards of parenthood must be quite substantial indeed.

....This paper has presented econometric evidence supporting a positive relationship between having children and life satisfaction. This result differs from the general view that the literature has held on the matter. Previous research failed to identify these positive effects because it did not consider the key role of individual characteristics, marital status in particular. For the average person, having children has a small and possibly zero effect on life satisfaction. For the average married person, however, the effect is large, positive and increasing in the number of children. The positive experience of married individuals is countered by the negative experiences of people who are separated, living as a couple or never-married singles.


Sunday, December 06, 2009

Pain Perception

The early edition of PNAS has this interesting piece on differences in pain perception. Here is the abstract:

Pain is a highly subjective experience that can be substantially influenced by differences in individual susceptibility as well as personality. How susceptibility to pain and personality translate to brain activity is largely unknown. Here, we report that the functional connectivity of two key brain areas before a sensory event reflects the susceptibility to a subsequent noxious stimulus being perceived as painful. Specifically, the prestimulus connectivity among brain areas related to the subjective perception of the body and to the modulation of pain (anterior insular cortex and brainstem, respectively) determines whether a noxious event is perceived as painful. Further, these effects of prestimulus connectivity on pain perception covary with pain-relevant personality traits. More anxious and pain-attentive individuals display weaker descending connectivity to pain modulatory brain areas. We conclude that variations in functional connectivity underlie personality-related differences in individual susceptibility to pain.


The Effects of Exercise on Cognition

The early edition of PNAS has this interesting study of Swedish men which suggests that cardiovascular fitness changes in early adultlife can enhance cognition. Here is the abstract:

During early adulthood, a phase in which the central nervous system displays considerable plasticity and in which important cognitive traits are shaped, the effects of exercise on cognition remain poorly understood. We performed a cohort study of all Swedish men born in 1950 through 1976 who were enlisted for military service at age 18 (N = 1,221,727). Of these, 268,496 were full-sibling pairs, 3,147 twin pairs, and 1,432 monozygotic twin pairs. Physical fitness and intelligence performance data were collected during conscription examinations and linked with other national databases for information on school achievement, socioeconomic status, and sibship. Relationships between cardiovascular fitness and intelligence at age 18 were evaluated by linear models in the total cohort and in subgroups of full-sibling pairs and twin pairs. Cardiovascular fitness, as measured by ergometer cycling, positively associated with intelligence after adjusting for relevant confounders (regression coefficient b = 0.172; 95% CI, 0.168–0.176). Similar results were obtained within monozygotic twin pairs. In contrast, muscle strength was not associated with cognitive performance. Cross-twin cross-trait analyses showed that the associations were primarily explained by individual specific, non-shared environmental influences (≥80%), whereas heritability explained <15% of covariation. Cardiovascular fitness changes between age 15 and 18 y predicted cognitive performance at 18 y. Cox proportional-hazards models showed that cardiovascular fitness at age 18 y predicted educational achievements later in life. These data substantiate that physical exercise could be an important instrument for public health initiatives to optimize educational achievements, cognitive performance, as well as disease prevention at the society level.


Tuesday, December 01, 2009

Health Innovations: Safety and Equality

This post brings together a number of issues I have been working on with respect to aging research.

In particular, I am interested in why so many people tend to eschew the field of biogerontology, and often express worries or concerns that really are (upon reflection) inappropriate, inconsistent or disproportionate given the nature of the stakes typically involved (e.g. the high risks of morbidity and mortality associated with the aging "status quo"). To bring these issues to the fore consider the following...

Many scientific studies demonstrate that health innovation X (I will conceal the details of what X is until later on) can reduce our risk of disease and increase life expectancy. X reduces, for example, the risk of cardiovascular disease, the #1 killer in the United States. Some estimate that a steady intake of X can actually add between 1-4 years to a person's life expectancy.

But there is a down side. Firstly, X also has some risks of harm. Some of these risks are very low, but others are high. For the most minor of harms, like discomfort (or even mild pain), fatigue, sweating and muscle and joint pain, these usually accompany taking X (though they are not long-lasting).

But X can also cause more severe harms. There is some basis for believing that X can be addictive. Furthermore, there are thousands of cases of X causing death. X1, for example, is a very popular version of X. In the United States millions of people regularly take X1 each week. X1 is a popular and cheap form of X. Sadly, more than 500,000 people in the US who take X1 are treated in emergency departments every year, and more than 700 people die as a result of X1. (source)

Even more tragically, children are at particularly high risk of injury by taking X1. Children 15 years and younger accounted for 59% of all the X1 injuries seen in US emergency departments. Now there are things we can do to mitigate some of these harms, but X1 is intrinsically risky. The only way to prevent any deaths from X1 would be to prohibit X1. But no one would propose that.

The proper administration of X could reduce many of the risks I have outlined above. But there is no way to completely eliminate the risks associated with X.

Let me now turn, just briefly, to concerns of equality. X is not equally accessible to everyone. Some people, because of where they live, or their family situation (single parent, etc.), or their income, or their education, or their job, have greater access to X than others. And this inequality in access to X can have a profound impact on a person's risk of disease and death. Having regular and easy access to X can make the difference between suffering a heart attack and dying at 65 or enjoying a healthy retirement. So having access to X really is a matter of life and death.

OK, so what we know about X is that (a) it can have enormous health benefits for both populations and individuals. The regular utilization of X can reduce the risk of disease and increase life expectancy. We also know (b) that X has some adverse side-effects, ranging from injury (which is common) to addiction and even death. And we know (c) that X is not equally available to all people. So what should we do?

Some might think that X is only imaginary. "Surely", one might conjecture, "if X kills people, including children, it would be banned!". Or the egalitarian might argue that "X should be equally accessible to all, and if it isn't, then no one should have access to X". These are common intuitions. Let's see how they fare when I reveal that the case in hand is a real one....

OK, let me now tell you what X is.................................... X is EXERCISE!!

Regular exercise is an important health intervention that can help reduce our risks of morbidity and mortality and extend life. But exercise is intrinsically risky. As long as bikes share roads with cars (bike riding was X1) there will be bike fatalities. But even if cars didn't exist, people can still fall off of bikes, or drop weights on their heads, get hit by lightening while playing baseball, suffer a heart attack or dehydration while running a marathon, sprain ankles, pull muscles, etc., etc., etc.

Do a "google" image search for "sports injuries" to see some of the 16 000 000 images (some more graphic than others) that make this point more vivid.

But despite seeing these images, and taking stock of all of the potential harmful effects of exercise, the pros of exercise *far outweigh* the potential harms. You are much more likely to die from an inactive life than you are from an active one. Hence why we (ought to) exercise!

Secondly, we are not all equally well placed to exercise regularly. Some people work at jobs that are outside and involve physically demanding work (like being a brick layer). Others have jobs with very long hours that involve sitting in front of a computer for most of the day (like academics!). Some people live in congested cities where clean air itself is a scarce resource, while others live in beautiful countrysides with amble opportunities for hiking and biking. Some people have an education that better positions them to make long-term decisions about their health (e.g. to regularly exercise or not). Others have family situations that can make exercising more of a challenge (e.g. providing the primary care for a child or sick parent) than it is for others. And some enjoy a higher income that permits them to buy a gym membership that others could not afford.

Concerns about safety and equal access do not lead us to eschew the importance of exercise. No one declares: "Someone died riding a bike so let's ban all bikes!", or "Jimmy broke his leg playing soccer so let's ban soccer!". No one invokes the precautionary principle in the context of exercise. Perhaps we don't because we are all familiar with the risks of exercising and the risks of inactivity. We know the latter outweigh the former by far.

The point of this exercise it get to us to realize what the benchmark is, in terms of safety and access, for a measure of preventative medicine that we all would applaud. Once one makes vivid the realities of exercise, then, and only then, can one begin to form considered judgements about concerns of safety and equality for a health innovation that conferred even bigger health benefits-- like a pill that retards human aging by mimicking calorie restriction.

Many people hesitate or even refuse to take drugs that could promote their health because they fear any potential adverse side-effects. Yesterday I spent 45 minutes waiting in line for the H1N1 shot. And I overheard many conversations about the fears and concerns people had after reading the info sheet about the flu vaccine. But what these people fail to reliaze is that, unlike the flu shot, getting in their car to drive home, or riding a bike, doesn't come with a small print warning label. These activities are much more risky, but they only feel safer because you do not read a warning label each time you do them.

If everything in life had a warning label they we wouldn't fixate so much on the potential adverse consequences of pharmaceuticals rather than other potentially risky interventions-- like exercise. Because the latter is considered "natural" we tend to view it as inherently safe. But the fact that one intervention is "natural" and a second "unnatural" doesn't make one safe and the other risky. The data, rather than our intuitions, ought to guide rational decision-making about health innovations.