I hope this newsletter finds you and your family well. Once again, I'm barely getting this newsletter out under the wire to still be in April, although it sure doesn't feel like spring (especially sitting at my daughter's softball game this morning) here in Mequon.
Patients often ask me what their ideal body composition should be. There are several ways to try to figure this out. We could use just the scale, but we know that isn't always the best answer. Body mass index (BMI) has been used as well, but as the first study shows, that also may not aways the best method. Read on for a better method.
Many of us have sedentary jobs, often looking at computers all day. Even if we exercise regularly, we are at increased risk of chronic diseases due to our sedentary work. The good news is that there is an easy way to reduce our risk in just a few minutes a day without breaking a sweat!
Finally, an inexpensive medicine for diabetes is getting a lot of press for its ability to possibly lower risk for cardiovascular disease, cancer and dementia. Is is a wonder drug?
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What is the Obesity Paradox?
the best way to measure risk
The "obesity paradox" is the unexpected finding of lower mortality in overweight and mildly or moderately obese individuals as determined by body mass index (BMI). Looking at only BMI as a marker of health is often quite inaccurate since it can be high in lean, muscular individuals. This study, from
Annals of Internal Medicine, gives more clarity to this paradox. Following all-cause mortality the researchers found that those with the lowest BMI but highest body fat had the highest risk of death.
Summary of findings:
Prior mortality studies have concluded that elevated body mass index (BMI) may improve survival. These studies were limited because they did not measure adiposity directly.
- Objective: To examine associations of BMI and body fat percentage (separately and together) with mortality.
- Design: Observational study.
- Setting: Manitoba, Canada.
- Participants: Adults aged 40 years or older referred for bone mineral density (BMD) testing.
- Measurements: Participants had dual-energy x-ray absorptiometry (DXA), entered a clinical BMD registry, and were followed using linked administrative databases. Adjusted, sex-stratified Cox models were constructed. Body mass index and DXA-derived body fat percentage were divided into quintiles, with quintile 1 as the lowest, quintile 5 as the highest, and quintile 3 as the reference.
- Results: The final cohort included 49 476 women (mean age, 63.5 years; mean BMI, 27.0 kg/m2; mean body fat, 32.1%) and 4944 men (mean age, 65.5 years; mean BMI, 27.4 kg/m2; mean body fat, 29.5%). Death occurred in 4965 women over a median of 6.7 years and 984 men over a median of 4.5 years. In fully adjusted mortality models containing both BMI and body fat percentage, low BMI (hazard ratio [HR], 1.44 [95% CI, 1.30 to 1.59] for quintile 1 and 1.12 [CI, 1.02 to 1.23] for quintile 2) and high body fat percentage (HR, 1.19 [CI, 1.08 to 1.32] for quintile 5) were associated with higher mortality in women. In men, low BMI (HR, 1.45 [CI, 1.17 to 1.79] for quintile 1) and high body fat percentage (HR, 1.59 [CI, 1.28 to 1.96] for quintile 5) were associated with increased mortality.
- Limitations: All participants were referred for BMD testing, which may limit generalizability. Serial measures of BMD and weight were not used. Some measures, such as physical activity and smoking, were unavailable.
- Conclusion: Low BMI and high body fat percentage are independently associated with increased mortality. These findings may help explain the counterintuitive relationship between BMI and mortality.
This study clearly demonstrates that BMI is definitely not the end-all for health. If fact, it can be misleading. This study of 49,476 women and 4944 men from Canada used BMI measurement along with DEXA scans (the gold standard for measuring body composition) to measure body fat percentage. They followed all-cause mortality and found that mortality increased as BMI decreased and body fat percentage increased. What this study suggests is that being frail with little muscle tone and high percentage of body fat puts you at higher risk of death. Percentage body fat is much more more important than BMI when we look at mortality risk.
A fit overweight person is better off than a thin couch potato.
Women should keep body fat % below 35% and men below 22%. You can check your body fat % with some bathroom scales. While these aren't as accurate as a DEXA scan, they can help you to keep track whether you are going up or down. You can also calculate your approximate body fat % with multiple different formulas. I have listed one formula below or use the link to plug in some simple body measurements along with your BMI to get an estimate. None of these formulas is perfect, but they can give you a ballpark idea where you are.
Women: (1.2 x BMI) + (.23 x age) - 5.4 = body fat percentage
Men: (1.2 x BMI) + (.23 x age) - 16.2 = body fat percentage
Take a Break for Better Health
Interrupting prolonged sitting beneficial
In today's world, many of us work in sedentary jobs, often on the phone or staring at a computer screen. Previous studies have shown that prolonged sitting is detrimental to our metabolic health, including increased risk of diabetes and heart disease. This study, from
Diabetes Care, found that interrupting prolonged sitting with three-minute bouts of light-intensity walking or simple resistance activities every 30 minutes improved cardiometabolic risk markers as compared to uninterrupted sitting for people with diabetes.
OBJECTIVE: To determine whether interrupting prolonged sitting with brief bouts of light-intensity walking (LW) or simple resistance activities (SRA) improves postprandial cardiometabolic risk markers in adults with type 2 diabetes (T2D).
RESEARCH DESIGN AND METHODS In a randomized crossover trial, 24 inactive overweight/obese adults with T2D (14 men 62 ± 6 years old) underwent the following 8-h conditions on three separate days (with 6-14 days washout): uninterrupted sitting (control) (SIT), sitting plus 3-min bouts of LW (3.2 km · h−1) every 30 min, and sitting plus 3-min bouts of SRA (half-squats, calf raises, gluteal contractions, and knee raises) every 30 min. Standardized meals were consumed during each condition. Incremental areas under the curve (iAUCs) for glucose, insulin, C-peptide, and triglycerides were compared between conditions.
RESULTS Compared with SIT, both activity-break conditions significantly attenuated iAUCs for glucose (SIT mean 24.2 mmol · h · L−1 [95% CI 20.4-28.0] vs. LW 14.8 [11.0-18.6] and SRA 14.7 [10.9-18.5]), insulin (SIT 3,293 pmol · h · L−1 [2,887-3,700] vs. LW 2,104 [1,696-2,511] and SRA 2,066 [1,660-2,473]), and C-peptide (SIT 15,641 pmol · h · L−1 [14,353-16,929] vs. LW 11,504 [10,209-12,799] and SRA 11,012 [9,723-12,301]) (all P < 0.001). The iAUC for triglycerides was significantly attenuated for SRA (P < 0.001) but not for LW (SIT 4.8 mmol · h · L−1 [3.6-6.0] vs. LW 4.0 [2.8-5.1] and SRA 2.9 [1.7-4.1]).
CONCLUSIONS Interrupting prolonged sitting with brief bouts of LW or SRA attenuates acute postprandial glucose, insulin, C-peptide, and triglyceride responses in adults with T2D. With poor adherence to structured exercise, this approach is potentially beneficial and practical.
Recent studies have shown that inactivity during the day is a significant risk factor for chronic disease. Prolonged sitting without interruption results in insulin resistance, weight gain and increased cardiac risk. We have typically stressed the benefits of structured exercise programs. While these programs are beneficial, we have also seen that 30 minutes of structured activity often isn't enough to overcome the detrimental effects of sitting for 8 hours daily. This study is important because it shows the benefits of brief episodes of physical activity throughout the day. Although the researchers looked only at diabetics, the findings should apply to everyone. Three minutes of activity for every 30 minutes of sitting significant improved insulin, triglyceride and inflammatory marker levels. This activity can be simple walking (strolling) or doing half-squats, calf raises, knee raises and gluteal contractions, which can be done at your desk. If you have a sedentary job, try pacing while you are on the phone, walking to your colleague instead of sending an email or IM, or doing some half-squats and calf raises while reading. It's an easy way to improve your health!
Benefits for Type 2 Diabetes of Interrupting Prolonged Sitting With Brief Bouts of Light Walking or Simple Resistance Activities Diabetes Care 2016 Apr 13;[EPub Ahead of Print], PC Dempsey, RN Larsen, P Sethi, JW Sacre, NE Straznicky, ND Cohen, E Cerin, GW Lambert, N Owen, BA Kingwell, DW Dunstan
A Medicine to Reduce Cancer Mortality Risk
Diabetes medication showed increased survival
Metformin, an inexpensive medication which is a first-line treatment for type 2 diabetes, may reduce risk of dying from cancer. This study, the
International Journal of Cancer, reviewed data from 145,826 postmenopausal women and found that those who took metformin had a significantly lower risk of dying from cancers.
Summary of findings:
- Findings from studies of metformin use with risk of cancer incidence and outcome provide mixed results; with few studies examined associations by recency of diabetes diagnosis or duration of medication use. Thus, in the Women's Health Initiative, we examined these associations and further explored whether associations differ by recency of diabetes and duration of metformin use. Cox regression models were used to estimate hazard ratios (HR) and their 95% confidence intervals. Diabetes was associated with higher risk of total invasive cancer (HR, 1.13; p < 0.001) and of several site-specific cancers (HR, 1.2-1.4, and up to over twofold). Diabetes was also associated with higher risk of death from cancer (HR, 1.46; p < 0.001). There was no overall difference in cancer incidence by diabetes therapy (p = 0.66). However, there was a lower risk of death from cancer for metformin users, compared to users of other medications, relative to women without diabetes, overall (HRs, 1.08 vs. 1.45; p = 0.007) and for breast cancer (HRs, 0.50 vs. 1.29; p = 0.05). Results also suggested that lower cancer risk associated with metformin may be evident only for a longer duration of use in certain cancer sites or subgroup populations. We provide further evidence that postmenopausal women with diabetes are at higher risk of invasive cancer and cancer death. Metformin users, particularly long-term users, may be at lower risk of developing certain cancers and dying from cancer, compared to users of other anti-diabetes medications. Future studies are needed to determine the long-term effect of metformin in cancer risk and survival from cancer.
The use of metformin for cancer has been mixed over the years with studies showing both
. This large study appears to show some potential benefit. Things to note are that all in the study already had diabetes. It was not used prospectively. Also, note that diabetics are at higher risk of cancers overall. In these diabetics it appears that using metformin did reduce risk of dying from cancer. Metformin is getting press due to a
underway to see if it is useful for reduction of cancer, cardiovascular disease and cognitive decline in non-diabetics. People are
trying lots of ways to get into the trial
. It certainly would be interesting if a medication, which costs a few cents a day, could extend lives through reductions in cancer, heart disease and dementia.
In healthy people, the liver produces glucose during fasting to maintain normal levels of blood sugar for energy. After people eat, the pancreas releases insulin, the hormone responsible for glucose absorption. Once insulin is released, the liver should turn down or turn off its glucose production, but in people with Type 2 diabetes, the liver fails to sense insulin and continues to make glucose. This is called insulin resistance and is caused by a glitch in the communication between liver and pancreas.Over time, this progresses from insulin resistance to outright diabetes.
Metformin, the front line therapy for uncomplicated Type 2 diabetes makes the liver more sensitive to insulin.
So the question is, should we all be taking metformin? If you are diabetic and tolerate it, the answer looks to be yes. Even better, avoid diabetes. Over 90% of diabetes is preventable and in many cases with weight loss it can even be reversed. This is certainly the best thing for prevention of chronic disease. The outcome of the ongoing study will be quite interesting to see if there is benefit in chronic disease in people without diabetes. In the mean time, what can we do to reduce our risk of the three things that we all worry about as we age: cardiovascular disease, cancer and dementia? If we look at the mechanism of metformin, it improves insulin sensitivity which is likely where the benefit comes from. High insulin levels are quite inflammatory, have been associated with tumor growth and we already know that diabetics have higher risk of cardiovascular disease, cancer and dementia. We can lower our insulin levels through changes in our diet and exercise and very likely get the same benefits as people taking metformin. Keeping our blood sugar and insulin levels down seems to be the key. Get exercise daily, both structured and intermittent (see first article), avoid sugar and simple starch in our diets, and maintain a healthy weight/body composition (see second article). It is likely that a variation of the Mediterranean diet rich in vegetables and fruits is the way to go (easy on the bread and pasta). This will keep our blood sugars and insulin levels low and has been shown to promote lower risk of cardiovascular disease, cancers and dementia.
Diabetes, metformin and incidence of and death from invasive cancer in postmenopausal women: Results from the women's health initiative (pages 1915-1927) Zhihong Gong, Aaron K. Aragaki, Rowan T. Chlebowski, JoAnn E. Manson, Thomas E. Rohan, Chu Chen, Mara Z. Vitolins, Lesley F. Tinker, Erin S. LeBlanc, Lewis H. Kuller, Lifang Hou, Michael J. LaMonte, Juhua Luo and Jean Wactawski-Wende International Journal of Cancer Volume 138, Issue 8, pages 1915-1927, 15 April 2016
Thank you for taking the time to read through this newsletter. I hope you have found this information useful as we work together to optimize your health.
Body composition using a body fat% seems to be a much better way to determine risk for chronic disease and is certainly better than a simple BMI. Some health clubs will measure body fat through caliper measurements or using a simple scale can be a reasonable way to get an idea where you are and whether you are at increased risk.
Taking time to move around during the day has been shown to reduce our risk of chronic diseases. There is no reason not to move during the day. Figure out ways to add a little activity frequently throughout your day. Your body will thank you.
Metformin does show some potential promise as a tool to fight some of the chronic diseases that afflict us. However, we can accomplish all of the same benefits without medication through changes in our diet and increased exercise. That sounds like a winner to me!
As always, if you have questions about anything in this newsletter or have topics you would like me to address, please feel free to contact me by email, phone, or just stop by!
To Your Good Health,
Mark Niedfeldt, M.D.