Goodarz Danaei

Bio: Goodarz Danaei is an academic researcher from Harvard University. The author has contributed to research in topics: Population & Risk factor. The author has an hindex of 59, co-authored 173 publications receiving 55837 citations. Previous affiliations of Goodarz Danaei include Institute for Health Metrics and Evaluation & Imperial College London.

Effect of physical activity on functional performance and knee pain in patients with osteoarthritis : analysis with marginal structural models.

Abstract: Background: A previous analysis of the Osteoarthritis Initiative study reported a dose-response relationship between physical activity and improved physical function in adults with knee osteoarthritis, using conventional statistical methods. These methods are subject to bias when confounders are affected by prior exposure. Methods: We used baseline and 1-, 2-, and 3-year follow-up data from the Osteoarthritis Initiative study of 2545 US adults with knee osteoarthritis recruited between 2004 and 2006 from 4 clinical sites. Physical activity was measured using the Physical Activity Scale for the Elderly, and outcomes were functional performance measured by the timed 20-meter walk test and self-reported knee pain measured by the Western Ontario and McMaster Universities Osteoarthritis Index. We estimated the effect of physical activity on each outcome using inverse probability-weighted (IPW) estimators of marginal structural models. For each outcome, we fitted 2 separate IPW models adjusting for concurrent or lagged confounders. Results: The mean differences in walking speed for the second, third, and fourth quartiles of physical activity relative to the first were 0.48 (95% confidence interval = -0.12 to 1.08), 0.45 (-0.23 to 1.13), and 0.46 (-0.29 to 1.22) meters/min based on the IPW model adjusting for concurrent confounders. When adjusting for lagged confounders, the results were 1.35 (0.64 to 2.07), 1.33 (0.54 to 2.14), and 1.26 (0.40 to 2.12). Both IPW models indicated that physical activity did not affect knee pain. Conclusions: Physical activity has no effect on knee pain and may have either a very small effect or no effect on functional performance in adults with knee osteoarthritis. Knee osteoarthritis is a leading cause of pain and disability in the elderly.1 There is no cure for osteoarthritis, and treatment is generally aimed at reducing pain and maintaining function.2 Several systematic reviews of randomized trials have demonstrated that exercise programs reduce pain and disability in the short term in patients with knee osteoarthritis.3–5 However, prospective observational studies are needed to evaluate the long-term effects of lifestyle physical activity among people with knee osteoarthritis. Using generalized estimating equations (GEE) to estimate a linear model, Dunlop et al 6 evaluated the effect of physical activity on subsequent 1-year functional performance in adults with knee osteoarthritis using 2-year follow-up data from the Osteoarthritis Initiative. The authors adjusted for the potential confounders available only at baseline, as well as the concurrent values of time-dependent confounders, and reported a dose-response relationship between physical activity and improved performance. However, standard methods for analysis of longitudinal data may lead to biased estimates when exposure affects a confounder, or when exposure is affected by prior outcome and affects future outcome.7–9 Both of these conditions are possible in the Osteoarthritis Initiative data, eg, physical activity may affect body mass index as a potential confounder and may also affect as well as be affected by functional performance. Marginal structural models overcome this problem by using inverse probability weighting.10,11 The aim of this study was to estimate the effect of physical activity on functional performance and knee pain in the Osteoarthritis Initiative cohort using inverse probability-weighted (IPW) estimators of marginal structural models.

Repositioning of the global epicentre of non-optimal cholesterol

Abstract: High blood cholesterol is typically considered a feature of wealthy western countries1,2. However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world3 and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health4,5. However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol—which is a marker of cardiovascular risk—changed from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95% credible interval 3.7 million–4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world.

Modeling Future Cardiovascular Disease Mortality in the United States: National Trends and Racial and Ethnic Disparities.

Abstract: Background—Accurate forecasting of cardiovascular disease mortality is crucial to guide policy and programming efforts. Prior forecasts often have not incorporated past trends in rates of reduction in cardiovascular disease mortality. This creates uncertainties about future trends in cardiovascular disease mortality and disparities. Methods and Results—To forecast US cardiovascular disease mortality and disparities to 2030, we developed a hierarchical bayesian model to determine and incorporate prior age, period, and cohort effects from 1979 to 2012, stratified by age, sex, and race, which we combined with expected demographic shifts to 2030. Data sources included the National Vital Statistics System, Surveillance, Epidemiology, and End Results (SEER) single-year population estimates, and US Bureau of Statistics 2012 national population projections. We projected coronary disease and stroke deaths to 2030, first on the basis of constant age, period, and cohort effects at 2012 values, as is most commonly do...

Global cancer statistics

Abstract: The global burden of cancer continues to increase largely because of the aging and growth of the world population alongside an increasing adoption of cancer-causing behaviors, particularly smoking, in economically developing countries. Based on the GLOBOCAN 2008 estimates, about 12.7 million cancer cases and 7.6 million cancer deaths are estimated to have occurred in 2008; of these, 56% of the cases and 64% of the deaths occurred in the economically developing world. Breast cancer is the most frequently diagnosed cancer and the leading cause of cancer death among females, accounting for 23% of the total cancer cases and 14% of the cancer deaths. Lung cancer is the leading cancer site in males, comprising 17% of the total new cancer cases and 23% of the total cancer deaths. Breast cancer is now also the leading cause of cancer death among females in economically developing countries, a shift from the previous decade during which the most common cause of cancer death was cervical cancer. Further, the mortality burden for lung cancer among females in developing countries is as high as the burden for cervical cancer, with each accounting for 11% of the total female cancer deaths. Although overall cancer incidence rates in the developing world are half those seen in the developed world in both sexes, the overall cancer mortality rates are generally similar. Cancer survival tends to be poorer in developing countries, most likely because of a combination of a late stage at diagnosis and limited access to timely and standard treatment. A substantial proportion of the worldwide burden of cancer could be prevented through the application of existing cancer control knowledge and by implementing programs for tobacco control, vaccination (for liver and cervical cancers), and early detection and treatment, as well as public health campaigns promoting physical activity and a healthier dietary intake. Clinicians, public health professionals, and policy makers can play an active role in accelerating the application of such interventions globally.

Global cancer statistics, 2012

Abstract: Cancer constitutes an enormous burden on society in more and less economically developed countries alike. The occurrence of cancer is increasing because of the growth and aging of the population, as well as an increasing prevalence of established risk factors such as smoking, overweight, physical inactivity, and changing reproductive patterns associated with urbanization and economic development. Based on GLOBOCAN estimates, about 14.1 million new cancer cases and 8.2 million deaths occurred in 2012 worldwide. Over the years, the burden has shifted to less developed countries, which currently account for about 57% of cases and 65% of cancer deaths worldwide. Lung cancer is the leading cause of cancer death among males in both more and less developed countries, and has surpassed breast cancer as the leading cause of cancer death among females in more developed countries; breast cancer remains the leading cause of cancer death among females in less developed countries. Other leading causes of cancer death in more developed countries include colorectal cancer among males and females and prostate cancer among males. In less developed countries, liver and stomach cancer among males and cervical cancer among females are also leading causes of cancer death. Although incidence rates for all cancers combined are nearly twice as high in more developed than in less developed countries in both males and females, mortality rates are only 8% to 15% higher in more developed countries. This disparity reflects regional differences in the mix of cancers, which is affected by risk factors and detection practices, and/or the availability of treatment. Risk factors associated with the leading causes of cancer death include tobacco use (lung, colorectal, stomach, and liver cancer), overweight/obesity and physical inactivity (breast and colorectal cancer), and infection (liver, stomach, and cervical cancer). A substantial portion of cancer cases and deaths could be prevented by broadly applying effective prevention measures, such as tobacco control, vaccination, and the use of early detection tests.