Oscar H. Franco

Public health benefits of strategies to reduce greenhouse-gas emissions: urban land transport.

We used Comparative Risk Assessment methods to estimate the health effects of alternative urban land transport scenarios for two settings-London, UK, and Delhi, India. For each setting, we compared a business-as-usual 2030 projection (without policies for reduction of greenhouse gases) with alternative scenarios-lower-carbon-emission motor vehicles, increased active travel, and a combination of the two. We developed separate models that linked transport scenarios with physical activity, air pollution, and risk of road traffic injury. In both cities, we noted that reduction in carbon dioxide emissions through an increase in active travel and less use of motor vehicles had larger health benefits per million population (7332 disability-adjusted life-years [DALYs] in London, and 12 516 in Delhi in 1 year) than from the increased use of lower-emission motor vehicles (160 DALYs in London, and 1696 in Delhi). However, combination of active travel and lower-emission motor vehicles would give the largest benefits (7439 DALYs in London, 12 995 in Delhi), notably from a reduction in the number of years of life lost from ischaemic heart disease (10-19% in London, 11-25% in Delhi). Although uncertainties remain, climate change mitigation in transport should benefit public health substantially. Policies to increase the acceptability, appeal, and safety of active urban travel, and discourage travel in private motor vehicles would provide larger health benefits than would policies that focus solely on lower-emission motor vehicles.

Combined impact of lifestyle factors on mortality: prospective cohort study in US women

Objective To evaluate the impact of combinations of lifestyle factors on mortality in middle aged women. Design Prospective cohort study. Setting Nurses’ health study, United States. Participants 77u2009782 women aged 34 to 59 years and free from cardiovascular disease and cancer in 1980. Main outcome measure Relative risk of mortality during 24 years of follow-up in relation to five lifestyle factors (cigarette smoking, being overweight, taking little moderate to vigorous physical activity, no light to moderate alcohol intake, and low diet quality score). Results 8882 deaths were documented, including 1790 from cardiovascular disease and 4527 from cancer. Each lifestyle factor independently and significantly predicted mortality. Relative risks for five compared with zero lifestyle risk factors were 3.26 (95% confidence interval 2.45 to 4.34) for cancer mortality, 8.17 (4.96 to 13.47) for cardiovascular mortality, and 4.31 (3.51 to 5.31) for all cause mortality. A total of 28% (25% to 31%) of deaths during follow-up could be attributed to smoking and 55% (47% to 62%) to the combination of smoking, being overweight, lack of physical activity, and a low diet quality. Additionally considering alcohol intake did not substantially change this estimate. Conclusions These results indicate that adherence to lifestyle guidelines is associated with markedly lower mortality in middle aged women. Both efforts to eradicate cigarette smoking and those to stimulate regular physical activity and a healthy diet should be intensified.

Non-vigorous physical activity and all-cause mortality: systematic review and meta-analysis of cohort studies

BACKGROUNDnAlthough previous studies have found physical activity to be associated with lower mortality, the dose-response relationship remains unclear. In this systematic review and meta-analysis we quantify the dose-response relationship of non-vigorous physical activity and all-cause mortality.nnnMETHODSnWe aimed to include all cohort studies in adult populations with a sample size of more than 10u2009000 participants that estimated the effect of different levels of light or moderate physical activity on all-cause mortality. We searched Medline, Embase, Cochrane (DARE), Web of Science and Global Health (June 2009). We used dose-response meta-regression models to estimate the relation between non-vigorous physical activity and mortality.nnnRESULTSnWe identified 22 studies that met our inclusion criteria, containing 977u2009925 (334u2009738 men and 643u2009187 women) people. There was considerable variation between the studies in their categorization of physical activity and adjustment for potential confounders. We found that 2.5u2009h/week (equivalent to 30u2009min daily of moderate intensity activity on 5 days a week) compared with no activity was associated with a reduction in mortality risk of 19% [95% confidence interval (CI) 15-24], while 7u2009h/week of moderate activity compared with no activity reduced the mortality risk by 24% (95% CI 19-29). We found a smaller effect in studies that looked at walking alone.nnnCONCLUSIONnBeing physically active reduces the risk of all-cause mortality. The largest benefit was found from moving from no activity to low levels of activity, but even at high levels of activity benefits accrue from additional activity.

Levels of vitamin D and cardiometabolic disorders: Systematic review and meta-analysis

Cardiometabolic disorders and vitamin D deficiency are becoming increasingly more prevalent across multiple populations. Different studies have suggested a potential association between abnormal vitamin D levels and multiple pathological conditions including cardiovascular diseases and diabetes. We aimed to evaluate the association between vitamin D levels, using 25-hydroxy vitamin D (25OHD) as an indicator of vitamin D status, and the presence of cardiometabolic disorders including cardiovascular disease, diabetes and metabolic syndrome. We performed a systematic review of the current literature on vitamin D and cardiometabolic disorders using the PubMed and Web of Knowledge databases in September 2009. Studies in adults looking at the effect of vitamin D levels on outcomes relating to cardiometabolic disorders were selected. We performed a meta-analysis to assess the risk of developing cardiometabolic disorders comparing the highest and lowest groups of serum 25OHD. From 6130 references we identified 28 studies that met our inclusion criteria, including 99,745 participants. There was moderate variation between the studies in their grouping of 25OHD levels, design and analytical approach. We found that the highest levels of serum 25OHD were associated with a 43% reduction in cardiometabolic disorders [OR 0.57, 95% (CI 0.48-0.68)]. Similar levels were observed, irrespective of the individual cardiometabolic outcome evaluated or study design. High levels of vitamin D among middle-age and elderly populations are associated with a substantial decrease in cardiovascular disease, type 2 diabetes and metabolic syndrome. If the relationship proves to be causal, interventions targeting vitamin D deficiency in adult populations could potentially slow the current epidemics of cardiometabolic disorders.

Association between fish consumption, long chain omega 3 fatty acids, and risk of cerebrovascular disease: systematic review and meta-analysis

Objective To clarify associations of fish consumption and long chain omega 3 fatty acids with risk of cerebrovascular disease for primary and secondary prevention. Design Systematic review and meta-analysis. Data sources Studies published before September 2012 identified through electronic searches using Medline, Embase, BIOSIS, and Science Citation Index databases. Eligibility criteria Prospective cohort studies and randomised controlled trials reporting on associations of fish consumption and long chain omega 3 fatty acids (based on dietary self report), omega 3 fatty acids biomarkers, or supplementations with cerebrovascular disease (defined as any fatal or non-fatal ischaemic stroke, haemorrhagic stroke, cerebrovascular accident, or transient ischaemic attack). Both primary and secondary prevention studies (comprising participants with or without cardiovascular disease at baseline) were eligible. Results 26 prospective cohort studies and 12 randomised controlled trials with aggregate data on 794u2009000 non-overlapping people and 34u2009817 cerebrovascular outcomes were included. In cohort studies comparing categories of fish intake the pooled relative risk for cerebrovascular disease for 2-4 servings a week versus ≤1 servings a week was 0.94 (95% confidence intervals 0.90 to 0.98) and for ≥5 servings a week versus 1 serving a week was 0.88 (0.81 to 0.96). The relative risk for cerebrovascular disease comparing the top thirds of baseline long chain omega 3 fatty acids with the bottom thirds for circulating biomarkers was 1.04 (0.90 to 1.20) and for dietary exposures was 0.90 (0.80 to 1.01). In the randomised controlled trials the relative risk for cerebrovascular disease in the long chain omega 3 supplement compared with the control group in primary prevention trials was 0.98 (0.89 to 1.08) and in secondary prevention trials was 1.17 (0.99 to 1.38). For fish or omega 3 fatty acids the estimates for ischaemic and haemorrhagic cerebrovascular events were broadly similar. Evidence was lacking of heterogeneity and publication bias across studies or within subgroups. Conclusions Available observational data indicate moderate, inverse associations of fish consumption and long chain omega 3 fatty acids with cerebrovascular risk. Long chain omega 3 fatty acids measured as circulating biomarkers in observational studies or supplements in primary and secondary prevention trials were not associated with cerebrovascular disease. The beneficial effect of fish intake on cerebrovascular risk is likely to be mediated through the interplay of a wide range of nutrients abundant in fish.

Chocolate consumption and cardiometabolic disorders: systematic review and meta-analysis

Objective To evaluate the association of chocolate consumption with the risk of developing cardiometabolic disorders. Design Systematic review and meta-analysis of randomised controlled trials and observational studies. Data sources Medline, Embase, Cochrane Library, PubMed, CINAHL, IPA, Web of Science, Scopus, Pascal, reference lists of relevant studies to October 2010, and email contact with authors. Study selection Randomised trials and cohort, case-control, and cross sectional studies carried out in human adults, in which the association between chocolate consumption and the risk of outcomes related to cardiometabolic disorders were reported. Data extraction Data were extracted by two independent investigators, and a consensus was reached with the involvement of a third. The primary outcome was cardiometabolic disorders, including cardiovascular disease (coronary heart disease and stroke), diabetes, and metabolic syndrome. A meta-analysis assessed the risk of developing cardiometabolic disorders by comparing the highest and lowest level of chocolate consumption. Results From 4576 references seven studies met the inclusion criteria (including 114u2009009 participants). None of the studies was a randomised trial, six were cohort studies, and one a cross sectional study. Large variation was observed between these seven studies for measurement of chocolate consumption, methods, and outcomes evaluated. Five of the seven studies reported a beneficial association between higher levels of chocolate consumption and the risk of cardiometabolic disorders. The highest levels of chocolate consumption were associated with a 37% reduction in cardiovascular disease (relative risk 0.63 (95% confidence interval 0.44 to 0.90)) and a 29% reduction in stroke compared with the lowest levels. Conclusions Based on observational evidence, levels of chocolate consumption seem to be associated with a substantial reduction in the risk of cardiometabolic disorders. Further experimental studies are required to confirm a potentially beneficial effect of chocolate consumption.

Ferritin Concentrations, Metabolic Syndrome, and Type 2 Diabetes in Middle-Aged and Elderly Chinese

CONTEXTnElevated ferritin concentrations frequently cluster with well-established risk factors of diabetes including obesity, metabolic syndrome, chronic inflammation, and altered circulating adipokines. Few studies, however, have systematically evaluated the effect of these risk factors on ferritin-diabetes association, particularly in Chinese populations.nnnOBJECTIVEnWe aimed to investigate, in a middle-aged and elderly Chinese population, whether elevated ferritin concentrations are associated with higher risk of metabolic syndrome and type 2 diabetes and to what extent the associations were influenced by obesity, inflammation, and adipokines.nnnDESIGN AND METHODSnWe conducted a population-based, cross-sectional survey of 3,289 participants aged 50-70 yr in Beijing and Shanghai in 2005. Fasting plasma ferritin, glucose, insulin, lipid profile, glycohemoglobin, inflammatory markers, adipokines, and dietary profile were measured.nnnRESULTSnMedian ferritin concentrations were 155.7 ng/ml for men and 111.9 ng/ml for women. After multiple adjustment, the odds ratios (ORs) were substantially higher for type 2 diabetes (OR 3.26, 95% confidence interval 2.36-4.51) and metabolic syndrome [OR 2.80 (95% confidence interval 2.24-3.49)] in the highest ferritin quartile compared with those in the lowest quartile. These associations remained significant after further adjustment for dietary factors, body mass index, inflammatory markers, and adipokines.nnnCONCLUSIONSnElevated circulating ferritin concentrations were associated with higher risk of type 2 diabetes and metabolic syndrome in middle-aged and elderly Chinese independent of obesity, inflammation, adipokines, and other risk factors. Our data support the crucial role of iron overload for metabolic diseases, even in a country with relatively high prevalence of iron deficiency.

Association between depressive symptoms and 25-hydroxyvitamin D in middle-aged and elderly Chinese

BACKGROUNDnVitamin D deficiency is recently speculated to play a role in the development of depression. Nevertheless, few studies have explored the association between blood 25-hydroxyvitamin D [25(OH)D] concentrations and depression in the general population. Therefore, we aimed to determine this association in middle-aged and elderly Chinese.nnnMETHODSnWe conducted a population-based cross-sectional study in 2005 in Beijing and Shanghai, China. Participants included 3262 community residents aged 50-70. Depressive symptoms were defined as a Center for Epidemiological Studies of Depression Scale (CES-D) score of 16 or higher. Circulating 25(OH)D concentrations were measured by radioimmunoassay.nnnRESULTSnThe prevalence of depressive symptoms was lower in the top tertile of 25(OH)D concentrations compared to the lowest tertile (7.2% vs. 11.1%) in the study population (odds ratio, 0.62; 95% confidence interval, 0.46-0.83; P for trend=0.002). This association was substantially attenuated after controlling for various confounding factors, and disappeared after including geographic location in the model. Stratified analysis by location did not find any association between depressive symptoms and 25(OH)D levels among participants from either Beijing or Shanghai.nnnLIMITATIONSnDue to the cross-sectional study design, causal relation remains unknown.nnnCONCLUSIONSnDepressive symptoms are not associated with 25(OH)D concentrations in middle-aged and elderly Chinese. Further prospective studies are required to determine whether they are correlated.

Adiposity and weight change in mid-life in relation to healthy survival after age 70 in women: prospective cohort study

Objective To examine the hypothesis that mid-life adiposity is associated with a reduced probability of maintaining an optimal health status among those who survive to older ages. Design Prospective cohort study. Setting The Nurses’ Health Study, United States. Participants 17u2009065 women who survived until at least the age of 70, provided information on occurrence of chronic disease, cognitive function, physical function, and mental health at older ages, and were free from major chronic diseases at mid-life (mean age was 50 at baseline in 1976). Main outcome measures Healthy survival to age 70 and over was defined as having no history of 11 major chronic diseases and having no substantial cognitive, physical, or mental limitations. Results Of the women who survived until at least age 70, 1686 (9.9%) met our criteria for healthy survival. Increased body mass index (BMI) at baseline was significantly associated with linearly reduced odds of healthy survival compared with usual survival, after adjustment for various lifestyle and dietary variables (P<0.001 for trend). Compared with lean women (BMI 18.5-22.9), obese women (BMI ≥30) had 79% lower odds of healthy survival (odds ratio 0.21, 95% confidence interval 0.15 to 0.29). In addition, the more weight gained from age 18 until mid-life, the less likely was healthy survival after the age of 70. The lowest odds of healthy survival were among women who were overweight (BMI ≥25) at age 18 and gained ≥10 kg weight (0.18, 0.09 to 0.36), relative to women who were lean (BMI 18.5-22.9) and maintained a stable weight. Conclusions These data provide evidence that adiposity in mid-life is strongly related to a reduced probability of healthy survival among women who live to older ages, and emphasise the importance of maintaining a healthy weight from early adulthood.

Associations of Physical Activity With Inflammatory Factors, Adipocytokines, and Metabolic Syndrome in Middle-Aged and Older Chinese People

Background— Inflammatory factors, adipocytokines, and the metabolic syndrome are important determinants of cardiometabolic disease. It remains unclear how physical activity is related to these risk factors. Our objective was to investigate single and joint associations of physical activity with inflammatory factors, adipocytokines, and the metabolic syndrome among middle-aged and older Chinese people. Methods and Results— A total of 3289 individuals (1458 men, 1831 women) 50 to 70 years of age participated in a population-based cross-sectional survey in Beijing and Shanghai, China. Levels of total physical activity were assessed with the International Physical Activity Questionnaire. High-sensitivity C-reactive protein, interleukin-6, tumor necrosis factor-&agr; receptor 2, adiponectin, and retinol-binding protein 4 were measured. The metabolic syndrome was defined using the updated National Cholesterol Education Program/Adult Treatment Panel III criteria for Asian Americans. Plasma concentrations of high-sensitivity C-reactive protein were 1.58, 1.74, and 1.27 mg/L (P=0.0138) and of adiponectin were 16.12, 16.20, and 17.21 mg/L (P=0.0078) among individuals with low, medium, and high levels of total physical activity, respectively, with adjustment for potential confounders. In the multivariable-adjusted logistic regression analyses, participants with higher levels of total physical activity had a lower risk of having the metabolic syndrome (odds ratio, 0.68; 95% confidence interval, 0.54 to 0.85; P for trend=0.001) compared with those with lower levels. Conclusions— Being physically active is associated with a better profile of inflammatory factors and adipocytokines and a reduced risk of having the metabolic syndrome among Chinese people.