Wednesday, October 27, 2010

Guest Commentary: Fitness for All

Michael Toscani, Pharm.D
Project Director
Jefferson School of Population Health

Obesity rates in the United States have reached epidemic proportions. The impact on our healthcare system in terms of type 2 diabetes and related cardiovascular disease will cost us billions in the next 10 years. One solution to this multi-factorial issue involves physical activity and exercise. However, there is a lack of consistent adherence to recommended physical activity guidelines.

Guidelines issued by the American College of Sports Medicine (ACSM) recommend 20 to 60 minutes of continuous aerobic activity three to five times a week, at 60% to 90% of your maximum heart rate. The ACSM also recommends doing resistance training two to three days a week. One set of eight to 10 exercises for major muscle groups (eight to 12 repetitions of each exercise) is ideal.

The second set of guidelines, from the U.S. Surgeon General, recommends that you accumulate 30 minutes of "moderate intensity" physical activity (such as walking, vacuuming, climbing stairs, and yard work) on most days – in two 15-minute bouts, three 10-minute bouts, or one 30-minute bout.

I’ve had the pleasure of being involved in a “Bootcamp” Fitness Class for the past 5 years. The creator of the program was a retired Major in the Marine Corps. His vision was to structure a variety of workouts that encompass the requirements of the guidelines but can be tailored for a wide group of participants at all levels of fitness. The group meets each day (M-F) from 6-7 AM at a local high school. All the workouts are outside, beginning with a 10-15 min warm up and ending with a cool down period. They are designed to offer a variety of training experiences and leadership opportunities for the participants. Participants work out at the level they are comfortable with.

A typical week is outlined below:
• Monday- Walk /run alternating speeds followed by abdominal core exercises
• Tuesday- Use a deck of cards (each suit corresponds to a different exercise designed to work large muscle groups, 2-14 reps each), 52 exercises
• Wednesday- Bike ride, run/walk or swim
• Thursday-Aerobic training and calisthenics/weight training using 4 corners of the workout area and fitness stations alternating periodically with a yoga class several months of the year.
• Friday- Leg exercises (squats, etc) combined with push ups, abdominal exercises and others selected by the group

Some of the results I have observed have been extraordinary for participants, who range in age from 35-65 years old. Some participants have many chronic medical conditions, including a renal transplant recipient and donor, lymphoma survivor, type 1 diabetes, hypertension, and dyslipidemias. Anecdotal results have included blood sugar and blood pressure reductions, normalized lipid profiles, weight loss, and improved cardiovascular fitness and a general sense of well being and confidence with continued participation for many months and years.

This approach and regimen is certainly not for all; however, the importance of having a “team fitness” approach undoubtedly improves attendance, adherence to fitness and dietary guidelines and could be a valuable piece of the complex puzzle of our health care system. Participants should always seek medical advice before engaging in these programs.

It would be great to see more randomized studies to test these observations and help provide more evidence to support individuals to achieve greater levels of fitness.

Hoo Rah !!!

Moisturizing Spritz Recipes

The moisturizing spritz is ideal for those with fine hair or those who prefer a lighter alternative to thick butters.  Additionally, it may be used to revive twists or another style that has gotten dry over time.  Below are a couple of quick, easy recipes.  Feel free to tweak to your own liking!

H2O Spritz
- water
- few drops of essential oil (your favorite)

ROSE-GLYCERIN Spritz
- 4 parts rosewater
- 1-2 parts glycerin

LEAVE-IN Spritz
- 5 parts water
- 1 part conditioner (your favorite)

THE WORKS Spritz
- 3-4 parts water
- 2 parts aloe vera juice
- 2 parts glycerin
- 1 part coconut oil
- 1 part olive oil
- few drops essential oil (your favorite)

NOTE: Some of these spritzes have a short shelf life (few days to a few weeks), so be sure not to create too much in one sitting.  Refrigeration may extend the shelf life a bit.

Twist Series: The Method I

More replies coming soon ... :o)

  • When you put in your shea butter mixture can you indicate how much exactly you put, because I find that when I do my hair I can't lean up on anything afterwards...lol Should it be a dime sized amount or should I not worry about the oil slick!
  • Can you show a picture to give any indication to how you part the twists?
  • When you say that you "reapply the whipped shea butter" weekly.. do you just rub the butter along the twisted hair? Or untwist, apply shea butter, and then retwist?
  • I find when I go to remoisturize my twists, whether I re-wet my hair and apply moisturizer or just apply the moisturizer alone, my twists are sooo frizzy and fuzzy afterwards. How can I prevent this? I have about 6 inches of hair just to give you an idea.

1. After washing, deep conditioning, and detangling, I plop my hair (while in 10-12 jumbo twists) in a towel. (Time: 1-2 hrs.)

2. After plopping, I undo each jumbo twist and apply a half-dollar-sized amount of whipped shea butter to each section.  Then I redo each jumbo twist and airdry (in a satin scarf) until 80-90% dry. (Time: several hours.)  I suggest applying enough butter to seal your hair and not so much to coat it.   
Plop, moisturize, then airdry in jumbo twists under scarf.


3. Once airdried 80-90% of the way, I begin to twist my hair.  I take down a jumbo twist and begin parting.  I find it easiest to part a horizontal section and then grab-and-go within that section.  I make smaller parts along the perimeter ... larger parts within the perimeter.  (Twist time: 1-3 hrs, depending on size.)  If needed, a small amount of whipped shea butter is reapplied to the ends of the twists only.
Part horizontally, then grab and go.


Smaller parts near nape.  (Not too small though.)

Long, slender parts along hairline.  (Too small = bad for my edges.)
4. When I reapply the whipped shea butter weekly (after a quick spritz with water), I just rub the butter along the twisted hair from the mid-shaft to the ends.  Afterwards, I immediately put my twists in 1-2 frenchbraids and wrap with a satin scarf to combat frizz formation.  Once the hair has "set", I take off the satin scarf. (Time: 30 minutes - 1hr.)

Monday, October 25, 2010

The amounts of water, carbohydrates, fat, and protein lost during a 30-day fast

When it comes to losing fat and maintaining muscle, at the same time, there are no shortcuts. The process generally has to be slow to be healthy. When one loses a lot of weight in a few days, most of what is being lost is water, followed by carbohydrates. (Carbohydrates are stored as liver and muscle glycogen.) Smaller amounts of fat and protein are also lost. The figure below, from Wilmore et al. (2007), shows the weights in grams of stored water, carbohydrates (glycogen), fat, and protein lost during a 30-day water fast.


On the first few days of the fast a massive amount of water is lost, even though drinking water is allowed in this type of fast. A significant amount of glycogen is lost as well. This is no surprise. About 2.6 g of water are lost for each 1 g of glycogen lost. That is, water is stored by the body proportionally to the amount of glycogen stored. People who do strength training on a regular basis tend to store more glycogen, particular in muscle tissue; this is a compensatory adaptation. Those folks also tend to store more water.

Not many people will try a 30-day fast. Still, the figure above has implications for almost everybody.

One implication is that if you use a bioimpedance scale to measure your body fat, you can bet that it will give you fairly misleading results if your glycogen stores are depleted. Your body fat percentage will be overestimated, because water and glycogen are lean body mass. This will happen with low carbohydrate dieters who regularly engage in intense physical exercise, aerobic or anaerobic. The physical exercise will deplete glycogen stores, which will typically not be fully replenished due to the low intake of carbohydrates.

Light endurance exercise (e.g., walking) is normally easier to maintain with a depleted “glycogen tank” than strength training, because light endurance exercise relies heavily on fat oxidation. It uses glycogen, but more slowly. Strength training, on the other hand, relies much more heavily on glycogen while it is being conducted (significant fat oxidation occurs after the exercise session), and is difficult to do effectively with a depleted “glycogen tank”.

Strength training practitioners often will feel fatigued, and will probably be unable to generate supercompensation, if their “glycogen tank” is constantly depleted. Still, compensatory adaptation can work its “magic” if one persists, and lead to long term adaptations that make athletes rely much more heavily on fat than the average person as a fuel for strength training and other types of anaerobic exercise. Some people seem to be naturally more likely to achieve this type of compensatory adaptation; others may never do so, no matter how hard they try.

Another implication is that you should not worry about short-term weight variations if your focus is on losing body fat. Losing stored water and glycogen may give you an illusion of body fat loss, but it will be only that – an illusion. You may recall this post, where body fat loss coupled with muscle gain led to some weight gain and yet to a much improved body composition. That is, the participants ended up leaner, even though they also weighed more.

The figure above also gives us some hints as to what happens with very low carbohydrate dieting (i.e., daily consumption of less than 20 grams of carbohydrates); at least at the beginning, before long term compensatory adaptation. This type of dieting mimics fasting as far as glycogen depletion is concerned, especially if protein intake is low, and has many positive short term health benefits. The depletion is not as quick as in a fast because a high fat and/or protein diet promotes higher rates of fat/protein oxidation and ketosis than fasting, which spare glycogen. (Yes, dietary fat spares glycogen. It also spares muscle tissue.) Still, the related loss of stored water is analogous to that of fasting, over a slightly longer period. The result is a marked weight loss at the beginning of the diet. This is an illusion as far as body fat loss is concerned.

Dietary protein cannot be used directly for glycogenesis; i.e., for replenishing glycogen stores. Dietary protein must first be used to generate glucose, through a process called gluconeogenesis. The glucose is then used for liver and muscle glycogenesis, among other things. This process is less efficient than glycogenesis based on carbohydrate sources (particularly carbohydrate sources that combine fructose and glucose), which is why for quite a few people (but not all) it is difficult to replenish glycogen stores and stimulate muscle growth on very low carbohydrate diets.

Glycogen depletion appears to be very healthy, but most of the empirical evidence seems to suggest that it is the depletion that creates a hormonal mix that is particularly health-promoting, not being permanently in the depleted state. In this sense, the extent of the glycogen depletion that is happening should be positively associated with the health benefits. And significant glycogen depletion can only happen if glycogen stores are at least half full to start with.

Reference

Wilmore, J.H., Costill, D.L., & Kenney, W.L. (2007). Physiology of sport and exercise. Champaign, IL: Human Kinetics.

Thursday, October 21, 2010

Twist Series: More to Come!

After two weeks of bunning, I'll be twisting again this weekend.  Answers to the following are on the way:

  • When you put in your shea butter mixture can you indicate how much exactly you put, because I find that when I do my hair I can't lean up on anything afterwards...lol Should it be a dime sized amount or should I not worry about the oil slick!
  • Can you show a picture to give any indication to how you part the twists?
  • When you say that you "reapply the whipped shea butter" weekly.. do you just rub the butter along the twisted hair? Or untwist, apply shea butter, and then retwist?
  • Do you have alot of shorter strands of hair that contribute to the frizzy look? I noticed that I have alot at the top and middle of my head and was wondering if that is natural or if something is wrong since to me it seems to be increasing in number!
  • Second, does having alot of single strand knots at the ends of my hair mean its definitely time for a trim?


If you have more questions, feel free to leave a comment with this post.  Until next week!

REVIEW #8: Jane Carter Nourish & Shine

NOTE:  I am not paid to review this and other products.  All products are purchased via my own pocket and curiosity.

Purpose: To moisturize dry hair, scalp, and/or skin.

Ingredients: shea, illipe, mango, kokum butters, grapefruit and pear essential oils, vitamins A, D, & E. 

Number of trials: Multiple (80% of the container)

How I used it:
• Seal my hair after washing or spritzing with water
• Create a braidout
• Moisturize dry elbows, knees, ankles, and lips

_____________
THE REVIEW:

My favorite characteristics about this product are the natural ingredients, mango-like smell, thickness, moisturizing capability, and versatility. For me, Jane Carter Nourish & Shine was most effective as a sealing agent after washing or wetting my hair ... AND on my skin (particularly, on my elbows, knees, and ankles) after bathing.

My not-so-favorite characteristic is the $22 price for the 4 oz.  This pricing may be due to the ingredients being all natural and shea butter being high on the list (number one to be exact).  Thus, one is paying for ingredient richness when purchasing this product.  Additionally, a little bit of Jane Carter Nourish & Shine goes a long, long way.

Will I purchase it again?  If it were cheaper and weren't a mixologist, then yes.  At the moment, I'm just fine whipping my own butters for less than half the price.  However, I do recommend Jane Carter Nourish & Shine to those desiring to purchase a thick, moisturizing, all-natural, rich, butter-based product that actually works. Here's a less expensive finding including more reviews on Amazon:







_____________

PROS: moisturizing, thick, versatile (use on skin, scalp, and hair), a little goes a long way, nice scent (if you like mango), shea butter as #1 ingredient
CONS: expensive, has a scent (if you're not a fan of mango or fragrances, in general)

RATING: Overall, I give the Jane Carter Nourish & Shine 4 out of 5 stars.  If it were inexpensive, I'd probably give it a full 5 stars.


Ideal for those with: thick hair prone to dryness
Not ideal for those with: fine hair, or hair prone to oiliness

Wednesday, October 20, 2010

Guest Commentary: Highlights from The Academy of Managed Care Pharmacy 2010 Educational Conference

Kellie Dudash, PharmD
Health Economics & Outcomes Research Fellow
Jefferson School of Population Health

The Academy of Managed Care Pharmacy (AMCP) 2010 Educational Conference was held last week in St. Louis, MO. The educational programming clearly reflected key contemporary issues in healthcare reform.

One of the most exciting presentations at the conference was an overview of a project that aims to demonstrate improved medication adherence for health plan members through pharmacy performance reporting and quality metric–focused interventions. The project is a collaboration between Highmark BlueCross BlueShield, Rite Aid Pharmacy, The Pharmacy Quality Alliance (PQA), CECity, and The University of Pittsburgh School of Pharmacy.

The literature indicates that poor medication adherence directly relates to increases in healthcare utilization and costs. Health plans usually tackle this issue by providing physicians with adherence reports for their patients at the population level. This study offers a novel approach by utilizing pharmacists at the point-of-dispensing to target non-adherent patients at the patient level.

The first phase of the project (2008) was rolled out in 50 Rite Aid Pharmacies in Western Pennsylvania. PQA-endorsed adherence measures for certain chronic conditions (heart disease, diabetes) were calculated for health plan members using Highmark claims data. CECity’s Lifetime™ platform translated the data into user-friendly electronic performance reports for Rite Aid pharmacists. The pharmacists could then compare the members’ adherence rates over time to those in their region and in all participating pharmacies.

Now that a system is in place to measure adherence in health plan members, phase two of the project (2010) will measure the impact of a psychosocial intervention on member adherence. Pharmacists in the intervention group will be trained in motivational interviewing techniques that will be used to motivate the non-adherent members. The primary outcome measured will be an increase in member adherence as measured by the PQA-endorsed adherence measures. Secondary outcomes include overall healthcare utilization calculated using member pharmacy and medical claims as well as member satisfaction with pharmacy services. The outcomes measured will be compared to health plan members in a control group in Central Pennsylvania who did not receive the intervention.

Currently, the data is only available at the pharmacy level. If they are able to measure data at the individual pharmacist level, exciting future directions for this project could include consumer reporting of pharmacist services and incentive reimbursement programs (pay-for-performance) for pharmacists.

As a profession, pharmacists have traditionally struggled with demonstrating the value of the cognitive services we offer. Retail pharmacists in particular are primarily rewarded based on prescription volume. It seems inappropriate to equate our professional value with hitting a target number that does not adequately account for the patient care services that go into each prescription.

I think most store managers would be open to rewarding pharmacists for cognitive services; but without easy to understand measures, the value of these services is consequently ignored. By creating a system to concretely measure the impact of pharmacists on improving patient outcomes, this pilot project is a step in the right direction.

Monday, October 18, 2010

Testing Times: Tuesday 2nd November

What links the following?




















Clive Parkinson will be sharing ideas from his new paper, A Brightly Coloured Bell-Jar, on Tuesday 2nd November at 5:00pm...he'd appreciate your feedback. Please email artsforhealth@mmu.ac.uk if you'd like to attend.

Friday, October 15, 2010

Healthy Hair on Youtube: Afrostory

Afrostory is another one of my favorite healthy hair youtubers.  She has the length and thick ends to show for it.  What's more?  She's a doctoral student specializing in an area about which she is clearly passionate - anthropology.  In the following video, Afrostory gives the "Inside Scoop on Healthy Hair".  Your thoughts?

Playlist for mid-October

Loo - Wavy
Currently playing: 2 weeks of semi-straight natural hair

Sounds like: Leela James

Chorus: Nightly plaits to maintain the style, daily buns, moisturize as needed
Leela James

Loo - Wavy Bun

Monday, October 11, 2010

Blood glucose levels in birds are high yet HbA1c levels are low: Can vitamin C have anything to do with this?

Blood glucose levels in birds are often 2-4 times higher than those in mammals of comparable size. Yet birds often live 3 times longer than mammals of comparable size. This is paradoxical. High glucose levels are generally associated with accelerated senescence, but birds seem to age much slower than mammals. Several explanations have been proposed for this, one of which is related to the formation of advanced glycation endproducts (AGEs).

Glycation is a process whereby sugar molecules “stick” to protein or fat molecules, impairing their function. Glycation leads to the formation of AGEs, which seem to be associated with a host of diseases, including diabetes, and to be implicated in accelerated aging (or “ageing”, with British spelling).

The graphs below, from Beuchat & Chong (1998), show the glucose levels (at rest and prior to feeding) and HbA1c levels (percentage of glycated hemoglobin) in birds and mammals. HbA1c is a measure of the degree of glycation of hemoglobin, a protein found in red blood cells. As such HbA1c (given in percentages) is a good indicator of the rate of AGE formation within an animal’s body.


The glucose levels are measured in mmol/l; they should be multiplied by 18 to obtain the respective measures in mg/dl. For example, the 18 mmol/l glucose level for the Anna’s (a hummingbird species) is equivalent to 324 mg/dl. Even at that high level, well above the level of a diabetic human, the Anna’s hummingbird species has an HbA1c of less than 5, which is lower than that for most insulin sensitive humans.

How can that be?

There are a few possible reasons. Birds seem to have evolved better mechanisms to control cell permeability to glucose, allowing glucose to enter cells very selectively. Birds also seem to have a higher turnover of cells where glycation and thus AGE formation results. The lifespan of red blood cells in birds, for example, is only 50 to 70 percent that of mammals.

But one of the most interesting mechanisms is vitamin C synthesis. Not only is vitamin C a powerful antioxidant, but it also has the ability to reversibly bind to proteins at the sites where glycation would occur. That is, vitamin C has the potential to significantly reduce glycation. The vast majority of birds and mammals can synthesize vitamin C. Humans are an exception. They have to get it from their diet.

This may be one of the many reasons why isolated human groups with traditional diets high in fruits and starchy tubers, which lead to temporary blood glucose elevations, tend to have good health. Fruits and starchy tubers in general are good sources of vitamin C.

Grains and seeds are not.

References

Beuchat, C.A., & Chong, C.R. (1998). Hyperglycemia in hummingbirds and its consequences for hemoglobin glycation. Comparative Biochemistry and Physiology Part A, 120(3), 409–416.

Holmes D.J., Flückiger, R., & Austad, S.N. (2001). Comparative biology of aging in birds: An update. Experimental Gerontology, 36(4), 869-883.

Guest Commentary: Awareness as a first step toward achieving population health



Valerie P. Pracilio, MPH
Project Manager for Quality Improvement
Jefferson School of Population Health



Recently, a number of colleagues and friends visited Philadelphia to celebrate the release of our latest book, Population Health: Creating a Culture of Wellness. As health care professionals, we are intimately familiar with the issues our system faces, and we are optimistic about the changes that are resulting from health reform efforts.

However, we still have a challenging road to travel to inform the public of the key issues and how they can be addressed at the population level. No mater what your position, I think we can all agree that achieving and maintaining health is our primary goal. By focusing on access to healthcare services when needed, good quality, safe outcomes when services are used, and avoiding the need for curative care, we can make great strides to improve health care.

The fact is, there is a strong army of individuals advocating for greater access, fewer barriers and better quality care, but the environment in which they are working presents a challenge. Population health is both a call to action and a solution. While individual patient needs are incredibly important, in this text we challenge you to broaden your perspective. We begin by providing background on the key issues and suggestions to achieve improvement. After all, awareness is the first step.

Just as we need to broaden our focus, we also need to recognize that developing population health strategies is not the work of individuals. The collaborative efforts of David B. Nash, JoAnne Reifsnyder, Ray Fabius and myself are a testament to that. At the book launch we had an opportunity to share what we learned while authoring and editing this text.

Dr. Nash highlighted the need for a book focused on population health and how the concept developed, JoAnne shared how we engaged key experts from a variety of fields to contribute, Ray mentioned the culture of wellness movement and how this book will help spread the message, and I highlighted the great work of our contributors, namely, Marty Romney and Henry Fader who were in attendance.

We also invited our colleagues to review the text and share their ideas about how we can turn strategies into solutions. We are at the tip of the iceberg, but we need YOUR help to improve population health!

How do you think can we can improve population health and create a culture of wellness? As always, we are interested in your comments.

Sunday, October 10, 2010

Greater Philadelphia Assoc of Health Underwriters-- GPAHU

Health Underwriters are the real sales force for insurance carriers across the nation. One of their largest membership organizations is here in Philadelphia--the Greater Philadelphia Assoc of Health Underwriters. I had the privilege of giving the plenary address to their entire 500 strong membership on Thursday, October 7th. I was asked to "sort out" health reform for them and to render my opinion about its implications in our marketplace. Well,no easy task for sure!!I told them my best understanding of the ACA is this---NO OUTCOME-NO INCOME---meaning, that we will face unprecedented levels of public accountability for what we do everyday as providers AND that we will come to be paid only after we achieve certain levels of outcome. Hence, No outcome--No income!!! This is a tough message--one filled with uncertainty and the possible erosion of professional autonomy too. Following my remarks, a leadership panel that included persons from Independence Blue Cross, Aetna, Cigna, United and Coventry made brief statements about their role and then we all took questions from a moderator. The insurance industry is clearly challenged by ACA and all of its implications. The carriers are in a watchful waiting mode, thinking about new markets and new opportunities too. GPAHU is an important part of the payment landscsape and the role of the broker under reform is still not clear. One thing IS clear---business as usual is out of the question!! DAVID NASH

Thursday, October 7, 2010

Healthy Hair on Youtube: Rusticbeauty

Rusticbeauty is one of my FAVORITE youtube hair ladies, and I've been following her since my early natural days.  She's achieved long, healthy natural via twisting and certainly has a hair care routine that works well for her.  In her earlier videos, she was big on using shea butter, Infusium 23, Organix, and coconut oil.  I share her channel with you for inspiration.

Some Rusticbeauty videos with which to start:
Ten tips for natural hair: video
Hair care regimen - pre-shampoo: video
Hair care regimen - after washing: video
Hair care regimen - after moisturizing: video
Hair care regimen - night-time prep: video

DISCLAIMER: Other people's hair care routine may or may not work for you.  Rather, use the suggested hair care routine as guidance and tweak for your hair.

Coming Soon: Jane Carter Nourish & Shine REVIEW

For hair and skin.  Review coming soon!

Winterize Your Conditioner!

Okay, it's not officially Winter yet, but it doesn't hurt to prepare ...

My obsession with shea butter does not stop at hair and body butters but extends to deep conditioners.  A few tablespoons will infuse an inexpensive conditioner with moisture and slip.  Try adding some melted shea butter to V05, Suave, or White Rain ... or mixing it with honey, egg, oil, or avocado to deep condition your hair this Winter ... and even Autumn!

Tuesday, October 5, 2010

The China Study II: Does calorie restriction increase longevity?

The idea that calorie restriction extends human life comes largely from studies of other species. The most relevant of those studies have been conducted with primates, where it has been shown that primates that eat a restricted calorie diet live longer and healthier lives than those that are allowed to eat as much as they want.

There are two main problems with many of the animal studies of calorie restriction. One is that, as natural lifespan decreases, it becomes progressively easier to experimentally obtain major relative lifespan extensions. (That is, it seems much easier to double the lifespan of an organism whose natural lifespan is one day than an organism whose natural lifespan is 80 years.) The second, and main problem in my mind, is that the studies often compare obese with lean animals.

Obesity clearly reduces lifespan in humans, but that is a different claim than the one that calorie restriction increases lifespan. It has often been claimed that Asian countries and regions where calorie intake is reduced display increased lifespan. And this may well be true, but the question remains as to whether this is due to calorie restriction increasing lifespan, or because the rates of obesity are much lower in countries and regions where calorie intake is reduced.

So, what can the China Study II data tell us about the hypothesis that calorie restriction increases longevity?

As it turns out, we can conduct a preliminary test of this hypothesis based on a key assumption. Let us say we compared two populations (e.g., counties in China), based on the following ratio: number of deaths at or after age 70 divided by number deaths before age 70. Let us call this the “ratio of longevity” of a population, or RLONGEV. The assumption is that the population with the highest RLONGEV would be the population with the highest longevity of the two. The reason is that, as longevity goes up, one would expect to see a shift in death patterns, with progressively more people dying old and fewer people dying young.

The 1989 China Study II dataset has two variables that we can use to estimate RLONGEV. They are coded as M005 and M006, and refer to the mortality rates from 35 to 69 and 70 to 79 years of age, respectively. Unfortunately there is no variable for mortality after 79 years of age, which limits the scope of our results somewhat. (This does not totally invalidate the results because we are using a ratio as our measure of longevity, not the absolute number of deaths from 70 to 79 years of age.) Take a look at these two previous China Study II posts (here, and here) for other notes, most of which apply here as well. The notes are at the end of the posts.

All of the results reported here are from analyses conducted using WarpPLS. Below is a model with coefficients of association; it is a simple model, since the hypothesis that we are testing is also simple. (Click on it to enlarge. Use the "CRTL" and "+" keys to zoom in, and CRTL" and "-" to zoom out.) The arrows explore associations between variables, which are shown within ovals. The meaning of each variable is the following: TKCAL = total calorie intake per day; RLONGEV = ratio of longevity; SexM1F2 = sex, with 1 assigned to males and 2 to females.



As one would expect, being female is associated with increased longevity, but the association is just shy of being statistically significant in this dataset (beta=0.14; P=0.07). The association between total calorie intake and longevity is trivial, and statistically indistinguishable from zero (beta=-0.04; P=0.39). Moreover, even though this very weak association is overall negative (or inverse), the sign of the association here does not fully reflect the shape of the association. The shape is that of an inverted J-curve; a.k.a. U-curve. When we split the data into total calorie intake terciles we get a better picture:


The second tercile, which refers to a total daily calorie intake of 2193 to 2844 calories, is the one associated with the highest longevity. The first tercile (with the lowest range of calories) is associated with a higher longevity than the third tercile (with the highest range of calories). These results need to be viewed in context. The average weight in this dataset was about 116 lbs. A conservative estimate of the number of calories needed to maintain this weight without any physical activity would be about 1740. Add about 700 calories to that, for a reasonable and healthy level of physical activity, and you get 2440 calories needed daily for weight maintenance. That is right in the middle of the second tercile.

In simple terms, the China Study II data seems to suggest that those who eat well, but not too much, live the longest. Those who eat little have slightly lower longevity. Those who eat too much seem to have the lowest longevity, perhaps because of the negative effects of excessive body fat.

Because these trends are all very weak from a statistical standpoint, we have to take them with caution. What we can say with more confidence is that the China Study II data does not seem to support the hypothesis that calorie restriction increases longevity.

Reference

Kock, N. (2010). WarpPLS 1.0 User Manual. Laredo, Texas: ScriptWarp Systems.

Notes

- The path coefficients (indicated as beta coefficients) reflect the strength of the relationships; they are a bit like standard univariate (or Pearson) correlation coefficients, except that they take into consideration multivariate relationships (they control for competing effects on each variable). Whenever nonlinear relationships were modeled, the path coefficients were automatically corrected by the software to account for nonlinearity.

- Only two data points per county were used (for males and females). This increased the sample size of the dataset without artificially reducing variance, which is desirable since the dataset is relatively small (each county, not individual, is a separate data point is this dataset). This also allowed for the test of commonsense assumptions (e.g., the protective effects of being female), which is always a good idea in a multivariate analyses because violation of commonsense assumptions may suggest data collection or analysis error. On the other hand, it required the inclusion of a sex variable as a control variable in the analysis, which is no big deal.

- Mortality from schistosomiasis infection (MSCHIST) does not confound the results presented here. Only counties where no deaths from schistosomiasis infection were reported have been included in this analysis. The reason for this is that mortality from schistosomiasis infection can severely distort the results in the age ranges considered here. On the other hand, removal of counties with deaths from schistosomiasis infection reduced the sample size, and thus decreased the statistical power of the analysis.