Found two more studies measuring diet pattern and mood disorders!
The first one is Dietary pattern and depressive symptoms in middle age from the British Journal of Psychiatry in 2009 (free full text, go take a look!). This paper is part of the large Whitehall II epidemiological study, where some 10,000 people were screened at baseline (phase 1) for all sorts of demographic characteristics, stress levels, health, lifestyle factors, blood pressure, and some labwork. Every 2&1/2 years or so, the study subjects received a postal questionnaire to fill out (phases 2,4,6,8), and every 5 years a questionnaire and a clinical examination were done (phases 3,5,7). In this paper, the data was taken from 3486 White European participants with data on dietary patterns and all covariates at phase 5 and depression at phase 7. The 175 Black and 331 Asian participants were excluded due to "differences in eating patterns." (!!!)
Dietary "pattern" was determined by a Food Frequency Questionnaire based on the one used in the Nurses Health Study (but changed up to include British sorts of foods - like bangers and mash, or crisps, or yorkshire pudding). Here's a good write-up addressing the (actually rather rigorous, but still hopeless) validity of the FFQ used in the Nurses Health Study. 127 food items were rated according to how often they were consumed - "never or less than once per month" up to "six or more times per day" - the 127 items were divided into 37 groups, and dietary patterns were identified using "principal component analysis" of the 37 groups, and statisticians gleefully addressed the data with graphs and scree plots and tweaks and nudges until a score pops out about each person's diet, falling into "whole foods" or the "processed foods" patterns.
"Whole foods" were diets consisting of vegetables, fruits and fish.
"Processed foods" were diets consisting of "high consumption of sweetened desserts, chocolates, fried food, processed meat, pies, refined grains, high fat dairy products, and condiments."
Depression measures were determined by a 20 question "Center for Epidemiologic Studies Depression Scale." People with a score higher than 15 were considered depressed.
Then the statisticians got a whack at the data again, adjusting for covariates such as age, gender, marital status, employment grade, education, smoking, physical activity, health status (based on clinical findings such as a high hemoglobin A1C (a measure of average blood glucose), blood pressure, being on antidepressants, etc.), a second "GHQ" depression subscale, and a cognitive score based on 65 question test.
Ready for the results yet? What do you think will turn out?
Patients with the highest intake of whole foods were less likely to be depressed (and this association wasn't affected much, actually, by adjusting for all the covariates, which is interesting - suggesting that the association with diet could be as important or more important than all those other covariates.). Patients with a high intake of processed food were much more likely to be depressed.
There is another interesting thing about this study. See, from just the above data, you don't know whether depressed people are too blue to do anything but sit around gorging on meat pies, sugar, and refined grains, or if the diet actually leads to the depression. The depression measures were repeated at phase 5 and phase 7, and when the 427 participants who were depressed at stage 5 were excluded, the data showed that the same people who had crappy diets but were not depressed (yet) at phase 5 were more likely to be depressed at phase 7. In addition, the researchers went back to the phase 3 data, and found no evidence that the dietary patterns in phase 5 were worse for the participants who were depressed at phase 3. These are clues that crappy diet precedes depressive symptoms, not the other way around.
All in all, a rather cool study, considering the limitations of epidemiology.
The second study is hot off the presses - Diet quality in bipolar disorder in a population-based sample of women from the Journal of Affective Disorders (I think this is the November issue - these are the corrected proofs available online before print). The subjects used were women from the Australian Geelong Osteoporosis Study (I blogged about them back in June). 1046 women randomly recruited from compulsory voting roles volunteered for this particular piece of the study. Each of the women were given the gold standard interview for diagnosis of psychiatric disorders - the SCID (non-patient edition). Patients with depression or anxiety were excluded, allowing for patients with bipolar disorder to be compared to those with no current (or lifetime) psychopathology.
Once again, a food frequency questionnaire was used, and the diets were broken up into "traditional" (vegetables, fruit, beef, lamb, fish, whole grains), "western" (meat pies, processed meats, pizza, chips, hamburgers, white bread, sugar, flavored milk drinks, and beer), and "modern" (fruits, salads, fish, yogurt, nuts, beans, tofu, and red wine). Blah blah blah logistic regression analyses and exposure variables were studiously applied and accounted for (can you tell I'm not an epidemiologist?).
Here's an interesting tidbit that I don't remember from the previous paper I blogged about in June - the researchers note that it was the absolute amount of western style foods that seemed to be related to the risk of depression rather than the amount as a proportion of overall energy consumption. Therefore, the researchers examined the data in this grouping as both absolute amounts, percentage of energy, and covariate confounding. Whew.
Bipolar disorder is less common than depressive or anxiety disorders, so only 23 women in the whole study qualified for the diagnosis (there were 332 with depression or anxiety and therefore excluded from this analysis, and 691 without depressive or anxiety disorders). Participants with bipolar disorder were younger and had higher average daily energy intake, though there was no difference in education, BMI, alcohol intake, education, socioeconomic status, smoking, and physical activity compared to those with no psychopathology. (Interesting - bipolar disorder and substance abuse are highly correlated so it is something to keep in mind that these 23 bipolar ladies didn't seem to smoke or drink more than the 691 "normals.")
Now the diet results! Individuals with a "modern" pattern were more likely to have a diagnosis of bipolar disorder, as were individuals with a "western" pattern, before and after adjustments for energy intake. A "traditional" dietary pattern was protective. These data held even when accounting for age.
As in the previous study (which I addressed in the comments in my previous blog post), the diets were also given a total "DQS" or dietary quality score, associated with how close the diets came to the national recommendations for good diets (similar to the USDA recommendations). DQS score of diets had no correlation with bipolar disorder, protective or not protective.
Overall, the authors noted (as I do now!) that the association with depressive, anxiety, and bipolar disorders are similar - a "traditional" diet being protective, and modern and western diets being similarly dismal. My theory is that an individual's response to diet would be based on genetic risk, so the inflammation level related to similar dietary choices would come out as different psychopathology depending on your genes.
The authors of the second study make note of the results of the first study I mentioned above - they think diet is causative, not a choice as a result of specific psychiatric illness. They note systemic inflammation, oxidative stress, and neurotrophin levels as potential explanations of the demonstrated associations between dietary quality and bipolar disorder. I agree. Wholeheartedly.
Eat real food, folks. It won't hurt. And maybe it will help.
Showing posts with label anxiety. Show all posts
Showing posts with label anxiety. Show all posts
Thursday, October 7, 2010
Sunday, July 18, 2010
Heart and Soul
UCSF medical school is running an 8 year prospective cohort study following patients with heart disease. The goal of the study is to gain some perspective on how psychological states affect your heart. A number of papers have been published (free full text! Suweet!), and today I'm focusing on one called "Scared to Death? Generalized Anxiety Disorder and Cardiovascular Events in Patients with Stable Coronary Heart Disease."
Anxiety has never had quite as much robust medical research that its big brother depression has. Perhaps because depression is easier to quantify and easier to treat. Anxiety tends to start in your youth, as you learn how to cope. By the time you end up getting treatment for it, you've probably had it for many years, even decades, and it becomes a part of who you are.
So it's no surprise that it is already known that depression and heart disease go hand in hand. If you have depression, you are more likely to develop heart disease (1), and if you have depression and heart disease, your heart disease will likely be worse (2).
But what studies there are of anxiety and heart disease show that anxiety is common among those with heart disease, and anxiety symptoms predict the amount of disability you will have. In the Heart and Soul study, 1015 people (mostly veterans from the VA medical centers) were followed for an average of 5.8 years. Generalized Anxiety Disorder (there are always specific criteria for these things, but in general, someone with GAD will worry a lot and have physical symptoms associated with worry, to the point that daily functioning is impaired. Panic attacks can also occur) was tested for via a Diagnostic Interview Schedule (that's a good test - a lot of studies will just use regular old scales, but the diagnostic interview is really the gold standard). In addition, everyone in the study had cholesterol measured, exercise capacity tested, a 24 hour heart monitor, 24 hour urine to measure norepinephrine and cortisol (chemicals associated with stress), C-reactive protein, and red blood cell percentage composition of fatty acids such as omega 3s, saturated fats, and omega 6s (which is the best way to figure out the fatty acid composition of the diet). Other patient data was also taken into account - age, sex, race, education, smoking, exercise, height, weight, and medications. Whew. All and all, pretty comprehensive, and all the latest technology. So far so good.
Each year, the investigators called up the study participants and asked about heart trouble. If anyone had an EKG, or a heart attack, any other "heart event" (specifically stroke, heart failure, MI, TIA, and death), the investigators got a hold of a copy of the medical records. Then they subjected the data to a tortuous round with the statisticians to try to sort out any confounding variables, and at the end, we get a bunch of nifty tables of information.
So what did they find?
10.4% of the participants met criteria for Generalized Anxiety Disorder (that's about in line with the literature - about 1/8 of people who visit their primary care doctor have GAD). Those who were anxious were also more likely to be younger, female, depressed, have better heart function on echocardiogram, take antidepressants and anxiety medicines, have lower omega 3 fatty acid levels in the red blood cell membranes, be less likely to exercise, and more likely to smoke. Also, they were less "adherent to medications" (what doctors call "noncompliance").
And the "heart events"? The annual rate of cardiovascular events was 6.6% for the people without generalized anxiety, and 9.6% of the people with GAD (p=0.03). That's annual! Meaning in 5.8 average years followed, there were a lot of medical records for the poor investigators to pore over!
And the confounding variables? (things which might cloud the statistical correlation between anxiety and heart disease) - male sex, heart function itself, exercise capacity, certain medication use, level of physical activity, and heart rate variability. So if those variables are "adjusted" for, you end up with a 62% greater rate of cardiovascular events for someone with generalized anxiety disorder and "stable" coronary heart disease. The raw data leaves you with a 74% greater rate of cardiovascular events. Either way, if you have heart disease, you are better off if you are more or less serene.
What do we take away from this paper? They have a discussion at the end worth reading. There's always a question in the medical literature about patients with psychiatric conditions - maybe they are sicker because they are too depressed or anxious to take care of themselves properly. They eat garbage, smoke more, exercise less. But, time after time, the studies show there is more to the connection than just crappy self-care. Interestingly, this study didn't find any link between physiologic markers of stress (the 24 hour urine measures, CRP, and heart rate variability) and the increased risk of anxiety disorders and heart disease. Smokin' and being lazy didn't explain the correlation either.
The authors postulated that a 24 hour urine wouldn't capture the risky "catecholamine spikes" of stress hormone that would be more likely to precipitate a heart attack. That makes sense. Then they speculate that anxious people are less likely to seek medical care (I sincerely doubt that one!), or are more likely to seek medical care (more realistic), thus the increase in recorded events was due to anxious people being more likely to consult their doctor with symptoms. Except, unfortunately, people with anxiety were more likely to be dead at the end of the 5.8 years of follow up, and that is one condition that isn't likely to be missed or uncounted.
Here we go: "It is also possible that there exists a common background origin to GAD symptoms and risk of cardiovascular disease." Also, GAD was associated with lower omega 3 fatty acid levels and depression, and "there is a clear association between lower omega 3 fatty acid levels and cardiovascular risk."
The conclusion? Take care of your anxiety! And eat some wild-caught salmon tonight.
Anxiety has never had quite as much robust medical research that its big brother depression has. Perhaps because depression is easier to quantify and easier to treat. Anxiety tends to start in your youth, as you learn how to cope. By the time you end up getting treatment for it, you've probably had it for many years, even decades, and it becomes a part of who you are.
So it's no surprise that it is already known that depression and heart disease go hand in hand. If you have depression, you are more likely to develop heart disease (1), and if you have depression and heart disease, your heart disease will likely be worse (2).
But what studies there are of anxiety and heart disease show that anxiety is common among those with heart disease, and anxiety symptoms predict the amount of disability you will have. In the Heart and Soul study, 1015 people (mostly veterans from the VA medical centers) were followed for an average of 5.8 years. Generalized Anxiety Disorder (there are always specific criteria for these things, but in general, someone with GAD will worry a lot and have physical symptoms associated with worry, to the point that daily functioning is impaired. Panic attacks can also occur) was tested for via a Diagnostic Interview Schedule (that's a good test - a lot of studies will just use regular old scales, but the diagnostic interview is really the gold standard). In addition, everyone in the study had cholesterol measured, exercise capacity tested, a 24 hour heart monitor, 24 hour urine to measure norepinephrine and cortisol (chemicals associated with stress), C-reactive protein, and red blood cell percentage composition of fatty acids such as omega 3s, saturated fats, and omega 6s (which is the best way to figure out the fatty acid composition of the diet). Other patient data was also taken into account - age, sex, race, education, smoking, exercise, height, weight, and medications. Whew. All and all, pretty comprehensive, and all the latest technology. So far so good.
Each year, the investigators called up the study participants and asked about heart trouble. If anyone had an EKG, or a heart attack, any other "heart event" (specifically stroke, heart failure, MI, TIA, and death), the investigators got a hold of a copy of the medical records. Then they subjected the data to a tortuous round with the statisticians to try to sort out any confounding variables, and at the end, we get a bunch of nifty tables of information.
So what did they find?
10.4% of the participants met criteria for Generalized Anxiety Disorder (that's about in line with the literature - about 1/8 of people who visit their primary care doctor have GAD). Those who were anxious were also more likely to be younger, female, depressed, have better heart function on echocardiogram, take antidepressants and anxiety medicines, have lower omega 3 fatty acid levels in the red blood cell membranes, be less likely to exercise, and more likely to smoke. Also, they were less "adherent to medications" (what doctors call "noncompliance").
And the "heart events"? The annual rate of cardiovascular events was 6.6% for the people without generalized anxiety, and 9.6% of the people with GAD (p=0.03). That's annual! Meaning in 5.8 average years followed, there were a lot of medical records for the poor investigators to pore over!
And the confounding variables? (things which might cloud the statistical correlation between anxiety and heart disease) - male sex, heart function itself, exercise capacity, certain medication use, level of physical activity, and heart rate variability. So if those variables are "adjusted" for, you end up with a 62% greater rate of cardiovascular events for someone with generalized anxiety disorder and "stable" coronary heart disease. The raw data leaves you with a 74% greater rate of cardiovascular events. Either way, if you have heart disease, you are better off if you are more or less serene.
What do we take away from this paper? They have a discussion at the end worth reading. There's always a question in the medical literature about patients with psychiatric conditions - maybe they are sicker because they are too depressed or anxious to take care of themselves properly. They eat garbage, smoke more, exercise less. But, time after time, the studies show there is more to the connection than just crappy self-care. Interestingly, this study didn't find any link between physiologic markers of stress (the 24 hour urine measures, CRP, and heart rate variability) and the increased risk of anxiety disorders and heart disease. Smokin' and being lazy didn't explain the correlation either.
The authors postulated that a 24 hour urine wouldn't capture the risky "catecholamine spikes" of stress hormone that would be more likely to precipitate a heart attack. That makes sense. Then they speculate that anxious people are less likely to seek medical care (I sincerely doubt that one!), or are more likely to seek medical care (more realistic), thus the increase in recorded events was due to anxious people being more likely to consult their doctor with symptoms. Except, unfortunately, people with anxiety were more likely to be dead at the end of the 5.8 years of follow up, and that is one condition that isn't likely to be missed or uncounted.
Here we go: "It is also possible that there exists a common background origin to GAD symptoms and risk of cardiovascular disease." Also, GAD was associated with lower omega 3 fatty acid levels and depression, and "there is a clear association between lower omega 3 fatty acid levels and cardiovascular risk."
The conclusion? Take care of your anxiety! And eat some wild-caught salmon tonight.
Thursday, June 24, 2010
Diet, Depression, and Anxiety
This post will focus on a single paper, published in March 2010 in the American Journal of Psychiatry: Association of Western and Traditional Diets With Depression and Anxiety in Women. (Thank you to Dr. Hale for pointing out the study). In the introduction, the authors make note that depression and anxiety are highly prevalent with other chronic dietary-related illnesses such as cardiovascular disease, obesity, and type 2 diabetes. At the same time, psychiatry lacks evidence-based prevention and treatment strategies based on dietary modification. That may be for the best, considering what has happened with obesity and type II diabetes over the past 30 years, but that is, in part, why I'm trying to get the information out, blog-wise.
So - the study! Well, these researchers in Australia hijacked an ongoing study, called the "Geelong Osteoporosis Study." Thousands of intrepid women were randomly picked from compulsory voting rolls, and all told, 1046 women ages 20-93 were followed for roughly 10 years for the diet and depression part. Each participant filled out yearly questionnaires about her diet. (Problem number one - imagine I gave you a questionnaire about your usual consumption of 74 foods, 6 alcoholic beverages, and the type of bread, dairy products, and fat spreads you used? How accurate could it be? The researchers say the "comprehensive food frequency questionnaire" was a validated instrument, but one must keep limitations in mind.)
Then, all participants were given a SCID (that's a standard structured clinical interview used to diagnose psychiatric disorders in research), and they looked for current diagnoses of major depressive disorder, dysthymia (a low-grade, ongoing depression), and anxiety disorders. Also, a wide variety of statistical analysis tools were used to account for so-called "covariates" such as socioeconomic status, physical activity, alcohol consumption, and smoking. (Problem number two - which is the major problem with any observational study - one can never really account for all the covariates. For example, people who drink moderate amounts of wine have less heart disease. Wine could be a factor in that. Or perhaps people who drink wine happen to exercise more. Or maybe people who drink wine also have magical hearts. We really don't know. If you take a group of people and force-feed some a glass of wine or two a day, and then tell another group to abstain, then see if there is a difference in heart disease between the two groups, then you have a prospective trial, and that's not the kind of data we're talking about with the current study I'm examining, which is an observational study. We end up with associations and correlations with such studies, which are interesting, but could be meaningless. Tom Naughton brings up this issue and the 2010 US dietary guidelines in this blog post. Don't click that link if you have extremely delicate sensibilities.) The researchers weighed and measured the height of all the participants also.
Results! Everyone's diet was analyzed and segregated into three basic groups - traditional, Western, and modern. Traditional diets were comprised of vegetables, fruit, beef, lamb, fish, and whole grain foods. A Western pattern was associated with meat pies (Australian fast food), processed meats, pizza, chips (I seriously do not know if they mean french fries or potato chips here - Australian readers, help me out!), hamburgers, white bread, sugar, flavored milk drinks, and beer. The "modern" diet consisted of fruits, salads, fish, tofu, beans, nuts, yogurt, and red wine (in other words, the people who read the news reports on all the observational studies out there...).
And the punch line? A traditional dietary pattern "was associated with a lower likelihood of depressive and anxiety disorders."
Traditional fruit, veggie, lamb, beef, fish and whole grain eaters had a 25% lower risk for major chronic disease (cardiovascular disease and cancer) after 10 years. They had 35% reduced odds for having major depression or dysthymia, and 32% reduced odds for anxiety disorders. The "Western" (junk) and "modern" (bean, fish, wine, and tofu) eaters fared about the same, but the Western eaters were slightly more depressed.
So there you have it! Beans and tofu and meat pies are correlated with depression and anxiety! Well, the authors of the study are pretty fair about the limitations of their design in the discussion. The do mention another study and how high-fat, high-sugar diets caused decreased hippocampal BDNF in animals, and that diets high in refined carbohydrates are associated with more inflammation. They also made note that a Mediterranean-style diet (which would roughly correspond to the traditional and modern diets) tends to decrease inflammatory markers.
I wonder what the data would look like without the whole grain eaters? Also, full fat dairy versus low fat dairy. Why do researchers never present the really interesting stuff to a paleolithic diet-inspired psychiatrist?
(A sobering thought is that I may be the only paleolithic-diet inspired psychiatrist).
So - the study! Well, these researchers in Australia hijacked an ongoing study, called the "Geelong Osteoporosis Study." Thousands of intrepid women were randomly picked from compulsory voting rolls, and all told, 1046 women ages 20-93 were followed for roughly 10 years for the diet and depression part. Each participant filled out yearly questionnaires about her diet. (Problem number one - imagine I gave you a questionnaire about your usual consumption of 74 foods, 6 alcoholic beverages, and the type of bread, dairy products, and fat spreads you used? How accurate could it be? The researchers say the "comprehensive food frequency questionnaire" was a validated instrument, but one must keep limitations in mind.)
Then, all participants were given a SCID (that's a standard structured clinical interview used to diagnose psychiatric disorders in research), and they looked for current diagnoses of major depressive disorder, dysthymia (a low-grade, ongoing depression), and anxiety disorders. Also, a wide variety of statistical analysis tools were used to account for so-called "covariates" such as socioeconomic status, physical activity, alcohol consumption, and smoking. (Problem number two - which is the major problem with any observational study - one can never really account for all the covariates. For example, people who drink moderate amounts of wine have less heart disease. Wine could be a factor in that. Or perhaps people who drink wine happen to exercise more. Or maybe people who drink wine also have magical hearts. We really don't know. If you take a group of people and force-feed some a glass of wine or two a day, and then tell another group to abstain, then see if there is a difference in heart disease between the two groups, then you have a prospective trial, and that's not the kind of data we're talking about with the current study I'm examining, which is an observational study. We end up with associations and correlations with such studies, which are interesting, but could be meaningless. Tom Naughton brings up this issue and the 2010 US dietary guidelines in this blog post. Don't click that link if you have extremely delicate sensibilities.) The researchers weighed and measured the height of all the participants also.
Results! Everyone's diet was analyzed and segregated into three basic groups - traditional, Western, and modern. Traditional diets were comprised of vegetables, fruit, beef, lamb, fish, and whole grain foods. A Western pattern was associated with meat pies (Australian fast food), processed meats, pizza, chips (I seriously do not know if they mean french fries or potato chips here - Australian readers, help me out!), hamburgers, white bread, sugar, flavored milk drinks, and beer. The "modern" diet consisted of fruits, salads, fish, tofu, beans, nuts, yogurt, and red wine (in other words, the people who read the news reports on all the observational studies out there...).
And the punch line? A traditional dietary pattern "was associated with a lower likelihood of depressive and anxiety disorders."
Traditional fruit, veggie, lamb, beef, fish and whole grain eaters had a 25% lower risk for major chronic disease (cardiovascular disease and cancer) after 10 years. They had 35% reduced odds for having major depression or dysthymia, and 32% reduced odds for anxiety disorders. The "Western" (junk) and "modern" (bean, fish, wine, and tofu) eaters fared about the same, but the Western eaters were slightly more depressed.
So there you have it! Beans and tofu and meat pies are correlated with depression and anxiety! Well, the authors of the study are pretty fair about the limitations of their design in the discussion. The do mention another study and how high-fat, high-sugar diets caused decreased hippocampal BDNF in animals, and that diets high in refined carbohydrates are associated with more inflammation. They also made note that a Mediterranean-style diet (which would roughly correspond to the traditional and modern diets) tends to decrease inflammatory markers.
I wonder what the data would look like without the whole grain eaters? Also, full fat dairy versus low fat dairy. Why do researchers never present the really interesting stuff to a paleolithic diet-inspired psychiatrist?
(A sobering thought is that I may be the only paleolithic-diet inspired psychiatrist).
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