Modifying effect of obesity on the association between sitting and incident diabetes in post-menopausal women

Unhealthy lifestyle associated with increased risk of macro- and micro-vascular comorbidities in patients with long-duration type 2 diabetes: results from the Taiwan Diabetes Registry

BACKGROUND

Unhealthy lifestyle has been associated with obesity and type 2 diabetes. Whereas its association with vascular complications in patients with long-duration of type 2 diabetes is still uncertain.

METHODS

A total of 1188 patients with long-duration of type 2 diabetes from the Taiwan Diabetes Registry (TDR) data were analyzed. We stratified the severity of unhealthy lifestyle via scoring three factors (sleep duration <7 or >9 h, sit duration ≥ 8h, and meal numbers ≥ with night snack) and analyzed their associations with the development of vascular complications using logistic regression analysis. Besides, we also included 3285 patients with newly diagnosed type 2 diabetes as the comparison.

RESULTS

Increased numbers of factors that stand for unhealthy lifestyle were significantly associated with the development of cardiovascular disease, peripheral arterial occlusion disease (PAOD) and nephropathy in patients with long-duration of type 2 diabetes. After adjusting multiple covariables, having ≥ 2 factors of unhealthy lifestyle remained significant associations with cardiovascular disease and PAOD, with an odds ratio (OR) of 2.09 (95% confidence interval [CI] 1.18-3.69) and 2.68 (95% CI 1.21-5.90), respectively. Among individual factor for unhealthy lifestyle behaviors, we revealed that eating ≥ 4 meals per day with night snack increased the risk of cardiovascular disease and nephropathy after multivariable adjustment (OR of 2.60, 95% CI 1.28-5.30; OR of 2.54, 95% CI 1.52-4.26, respectively). Whereas sit duration for ≥ 8 h per day increased the risk of PAOD (OR of 4.32, 95% CI 2.38-7.84).

CONCLUSION

Unhealthy lifestyle is associated with increased prevalence of macro- and micro-vascular comorbidities in Taiwanese patients with long-duration type 2 diabetes.

Modelling the potential health and economic benefits of reducing population sitting time in Australia

Background

Strong evidence indicates that excessive time spent sitting (sedentary behaviour) is detrimentally associated with multiple chronic diseases. Sedentary behaviour is prevalent among adults in Australia and has increased during the COVID-19 pandemic. Estimating the potential health benefits and healthcare cost saving associated with reductions in population sitting time could be useful for the development of public health initiatives.

Methods

A sedentary behaviour model was developed and incorporated into an existing proportional, multi-state, life table Markov model (ACE-Obesity Policy model). This model simulates the 2019 Australian population (age 18 years and above) and estimates the incidence, prevalence and mortality of five diseases associated with sedentary behaviour (type 2 diabetes, stroke, endometrial, breast and colorectal cancer). Key model inputs included population sitting time estimates from the Australian National Health Survey 2014–2015, healthcare cost data from the Australian Institute of Health and Welfare (2015) and relative risk estimates assessed by conducting literature reviews and meta-analyses. Scenario analyses estimated the potential change in disease incidence as a result of changes in population sitting time. This, in turn, resulted in estimated improvements in long term health outcomes (Health-adjusted life years (HALYs)) and healthcare cost-savings.

Results

According to the model, if all Australian adults sat no more than 4 h per day, the total HALYs gained would be approximately 17,211 with health care cost savings of approximately A$185 million over one year. Under a more feasible scenario, where sitting time was reduced in adults who sit 4 or more hours per day by approximately 36 min per person per day (based on the results of the Stand Up Victoria randomised controlled trial), potential HALYs gained were estimated to be 3,670 and healthcare cost saving could reach A$39 million over one year.

Conclusions

Excessive sedentary time results in considerable population health burden in Australia. This paper describes the development of the first Australian sedentary behaviour model that can be used to predict the long term consequences of interventions targeted at reducing sedentary behaviour through reductions in sitting time. These estimates may be used by decision makers when prioritising healthcare resources and investing in preventative public health initiatives.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12966-022-01276-2.

A Study Using Power Cycling on the Affective Responses of a Low-Volume High-Intensity Interval Training to Male Subjects with Type 2 Diabetes in Different Physical Activity Status

High-intensity interval training (HIIT) has been shown in studies to enhance glucose management and cardiovascular well-being in patients with type 2 diabetes. In this study, we used power cycling to assess the physical activity levels of men with type 2 diabetes during a single low-volume HIIT session. First, fifty-six men with type 2 diabetes volunteered to take part in the study, and they were split into two groups based on the International Physical Activity Scale Short Form (IPA). To the first 1-4 labor bouts, both the sufficiently physically active and insufficiently physically active groups exhibited equal positive emotional reactions (p > 0.05). However, over time (about 5-10 times), both of them showed reduced emotional reactions, with a significant difference (p < 0.01). The insufficiently physically active group had lower mean emotional response, lowest effective response, and maximum effective response values than the sufficiently physically active group (p < 0.001), while the difference in RPE between the two groups was not statistically significant (p > 0.05). From the standpoint of emotional response, the proposed model shows that HIIT or reduced volume HIIT exercise prescriptions should be utilized with caution in physical activity programs for novices and less active and chronically sick persons. The frequency, intensity, and effects of low-volume HIIT on individuals' emotional reactions and health conditions in the T2DM group are also investigated. Furthermore, this low-volume HIIT program can be successfully applied in the real-world setting of people who are not physically active enough or who are chronically unwell.

[Effects of physical activity and decreased sedentary behaviours in menopausal women. Postmenopausal women management: CNGOF and GEMVi clinical practice guidelines]

The purpose of this chapter is to examine, in postmenopausal women, the effect of physical activity (PA) on overall mortality, cardiovascular mortality and prevention of cardiovascular disease, bone health and body composition. An analysis of the scientific literature was carried out and more than 100 studies were selected. In postmenopausal women, regular endurance PA significantly reduced overall and cardiovascular mortality. It is effective in primary and tertiary prevention. Regarding bone health, combined exercises combining weight-bearing exercises with impacts associated with muscle strengthening are the most effective to maintain or improve bone mineral density and prevent fractures. In terms of body composition, regular endurance or combined PA (endurance+muscle strengthening) decreases visceral fat regardless of BMI, and this in the absence of caloric restriction. For muscle mass, only muscle strengthening or combined training (endurance+muscle strengthening) have shown their effectiveness in slowing down the loss of muscle mass or even in increasing it. In all cases, the minimum duration of PA is 12 weeks and above all, it must be continued so that the effects are maintained over the long term. All these parameters will also be improved with a reduction in time spent sitting, regardless of the level of PA. No study has reported a major incident related to the practice of moderate to high intensity levels of PA, provided that certain precautions are observed, the main one being with regard to cardiovascular risk. The recommendations for postmenopausal women are a reduction in sedentary behaviour associated with specific recommendations for regular physical activity.

Sedentary Behavior and Diabetes Risk Among Women Over the Age of 65 Years: The OPACH Study

OBJECTIVE

To evaluate whether sedentary time (ST) and/or sedentary behavior patterns are related to incident diabetes in the U.S.'s oldest age-groups.

RESEARCH DESIGN AND METHODS

Women without physician-diagnosed diabetes (n = 4,839, mean ± SD age = 79 ± 7 years) wore accelerometers for ≥4 days and were followed up to 6 years for self-reported newly diagnosed diabetes requiring treatment with medications. Hazard ratios (HRs) for incident diabetes were estimated across quartiles of accelerometer-measured ST and mean bout duration with use of Cox proportional hazards models. We conducted isotemporal substitution analyses using Cox regression and tested associations with risk for diabetes after statistically replacing ST with light physical activity (PA) or moderate-to-vigorous PA (MVPA) and after replacing light PA with MVPA.

RESULTS

During 20,949 person-years, 342 diabetes cases were identified. Women in ST quartile (Q)2, Q3, and Q4 (vs. Q1) had incident diabetes HR 1.20 (95% CI 0.87-1.65), 1.33 (0.97-1.82), and 1.21 (0.86-1.70); P _trend = 0.04. Respective HRs following additional adjustment for BMI and MVPA were 1.04 (95% CI 0.74-1.47), 1.04 (0.72-1.50), and 0.85 (0.56-1.29); P _trend = 0.90. Fully adjusted isotemporal substitution results indicated that each 30 min of ST replaced with MVPA (but not light PA) was associated with 15% lower risk for diabetes (HR 0.85 [95% CI 0.75-0.96]; P = 0.01); the HR for replacing 30 min of light PA with MVPA was 0.85 (95% CI 0.73-0.98); P = 0.03. Mean bout duration was not associated with incident diabetes.

CONCLUSIONS

Statistically replacing ST or light PA with MVPA was associated with lower diabetes risk in older women. While reducing ST is important for several health outcomes, results indicate that to reduce diabetes risk among older adults, the primary public health focus should be on increasing MVPA.

Long-Term and Acute Benefits of Reduced Sitting on Vascular Flow and Function

PURPOSE

Sedentary behavior increases the risk for cardiovascular and cerebrovascular disease. To understand potential benefits and underlying mechanisms, we examined the acute and long-term effect of reduced sitting intervention on vascular and cerebrovascular function.

METHODS

This prospective study included 24 individuals with increased cardiovascular risk (65 ± 5 yr, 29.8 ± 3.9 kg·m-2). Before and after 16-wk reduced sitting, using a mobile health device with vibrotactile feedback, we examined (i) vascular function (flow-mediated dilation [FMD]), (ii) cerebral blood flow velocity (CBFv, transcranial Doppler), and (iii) cerebrovascular function (cerebral autoregulation [CA] and cerebral vasomotor reactivity [CVMR]). To better understand potential underlying mechanisms, before and after intervention, we evaluated the effects of 3 h sitting with and without light-intensity physical activity breaks (every 30 min).

RESULTS

The first wave of participants showed no change in sedentary time (n = 9, 10.3 ± 0.5 to 10.2 ± 0.5 h·d-1, P = 0.87). Upon intervention optimization by participants' feedback, the subsequent participants (n = 15) decreased sedentary time (10.2 ± 0.4 to 9.2 ± 0.3 h·d-1, P < 0.01). This resulted in significant increases in FMD (3.1% ± 0.3% to 3.8% ± 0.4%, P = 0.02) and CBFv (48.4 ± 2.6 to 51.4. ±2.6 cm·s-1, P = 0.02), without altering CA or CVMR. Before and after the 16-wk intervention, 3-h exposure to uninterrupted sitting decreased FMD and CBFv, whereas physical activity breaks prevented a decrease (both P < 0.05). CA and CVMR did not change (P > 0.20).

CONCLUSION

Long-term reduction in sedentary behavior improves peripheral vascular function and cerebral blood flow and acutely prevents impaired vascular function and decreased cerebral blood flow. These results highlight the potential benefits of reducing sedentary behavior to acutely and chronically improve cardio- or cerebrovascular risk.

Associations of Number of Daily Eating Occasions with Type 2 Diabetes Risk in the Women's Health Initiative Dietary Modification Trial

BACKGROUND

Over 23 million Americans have type 2 diabetes (T2D). Eating habits such as breakfast consumption, time-restricted eating, and limiting daily eating occasions have been explored as behaviors for reducing T2D risk, but prior evidence is inconclusive.

OBJECTIVES

Our objectives were to examine associations between number of daily eating occasions and T2D risk in the Women's Health Initiative Dietary Modification Trial (WHI-DM) and whether associations vary by BMI, age, or race/ethnicity.

METHODS

Participants were postmenopausal women in the WHI-DM who comprised a 4.6% subsample completing 24-h dietary recalls (24HRs) at years 3 and 6 as part of trial adherence activities (n = 2159). Numbers of eating occasions per day were obtained from the year 3 24HRs, and participants were grouped into approximate tertiles as 1-3 (n = 795), 4 (n = 713), and ≥5 (n = 651) daily eating occasions as the exposure. Incident diabetes was self-reported on semiannual questionnaires as the outcome.

RESULTS

Approximately 15% (15.4%, n = 332) of the WHI-DM 24HR cohort reported incident diabetes at follow-up. Cox proportional hazards regression tested associations of eating occasions with T2D adjusted for neighborhood socioeconomic status, BMI, waist circumference, race/ethnicity, family history of T2D, recreational physical activity, Healthy Eating Index-2005, 24HR energy intake, and WHI-DM arm. Compared with women reporting 1-3 meals/d, those consuming 4 meals/d had a T2D HR = 1.38 (95% CI: 1.03, 1.84) without further increases in risk for ≥5 meals/d. In stratified analyses, associations for 4 meals/d compared with 1-3 meals/d were stronger in women with BMI <30.0 kg/m2 (HR = 1.55; 95% CI: 1.00, 2.39) and women aged ≥60 (HR = 1.61; 95% CI: 1.11, 2.33).

CONCLUSIONS

Four meals per day compared with 1-3 meals/d was associated with increased risk of T2D in postmenopausal women, but no dose-response effect was observed for additional eating occasions. Further studies are needed to understand eating occasions in relation to T2D risk.

A Case for Promoting Movement Medicine: Preventing Disability in the LIFE Randomized Controlled Trial

BACKGROUND

The movement profile of older adults with compromised function is unknown, as is the relationship between these profiles and the development of major mobility disability (MMD)-a critical clinical outcome. We first describe the dimensions of movement in older adults with compromised function and then examine whether these dimensions predict the onset of MMD.

METHODS

Older adults at risk for MMD (N = 1,022, mean age = 78.7 years) were randomized to receive a structured physical activity intervention or health education control. We assessed MMD in 6-month intervals (average follow-up of 2.2 years until incident MMD), with activity assessed at baseline, 6-, 12- and 24-month follow-up via accelerometry.

RESULTS

A principal components analysis of 11 accelerometer-derived metrics yielded three components representing lifestyle movement (LM), extended bouts of moderate-to-vigorous physical activity (MVPA), and stationary body posture. LM accounted for the greatest proportion of variance in movement (53%). Within health education, both baseline LM (HR = 0.74; 95% CI 0.62 to 0.88) and moderate-to-vigorous physical activity (HR = 0.69; 95% CI 0.54 to 0.87) were associated with MMD, whereas only LM was associated with MMD within physical activity (HR = 0.74; 95% CI 0.61 to 0.89). There were similar nonlinear relationships present for LM in both physical activity and health education (p < .04), whereby risk for MMD was lower among individuals with higher levels of LM.

CONCLUSIONS

Both LM and moderate-to-vigorous physical activity should be central in treatment regimens for older adults at risk for MMD.

TRIAL REGISTRATION

clinicaltrials.gov Identifier NCT01072500.

Hours lying down per day, as a proxy for sedentary behaviour and risk of diabetes in young and middle-aged adults in Norway: an 11-year follow-up of the HUNT study

OBJECTIVE

We aimed to examine relationship between hours lying down per day, as a proxy for sedentary behaviour and risk of diabetes in young and middle-aged adults, and to assess if leisure-time physical activity and body mass index (BMI) modified this relationship.

DESIGN

A population-based prospective cohort study.

SETTING

Nord-Trøndelag, Norway.

PARTICIPANTS

The cohort included 17 058 diabetes-free adults, at an age of 20-55 years in 1995-1997, who were followed-up to 2006-2008.

PRIMARY OUTCOME MEASURES

Incident diabetes was defined by self-report of diabetes or non-fasting glucose levels greater than 11 mmol/L at the follow-up.

METHODS

Multivariable logistic regression models were used to obtain OR with 95% CI for risk of diabetes by the categories of hours lying down (≤7, 8 and ≥9 hours/day).

RESULTS

362 individuals (2.1%) developed diabetes during an average of 11-year follow-up. Individuals who reported lying down ≥9 hours/day had an adjusted OR of 1.35 (95% CI 1.01 to 1.80) for incident diabetes compared with those lying down 8 hours/day. Lying down ≤7 hours/day was not associated with the risk of diabetes. In analysis stratified by physical activity, the ORs associated with lying down ≥9 hours/day were 1.41 (95% CI 1.05 to 1.90) and 0.90 (95% CI 0.23 to 3.55), respectively, among the less active and highly active individuals (p_interaction=0.048). There was little evidence that the association differed by BMI status (p_interaction=0.62).

CONCLUSIONS

Prolonged hours lying down per day was associated with an increased risk of diabetes in young and middle-aged adults. The positive association appeared to be modified by physical activity but not by BMI.

Association of total sedentary behaviour and television viewing with risk of overweight/obesity, type 2 diabetes and hypertension: A dose-response meta-analysis

AIMS

To explore the quantitative dose-response association of total sedentary behaviour and television viewing with overweight/obesity, type 2 diabetes and hypertension in a meta-analysis.

MATERIALS AND METHODS

We searched three databases to identify English-language reports that assessed the association of total sedentary behaviour or television viewing with the aforementioned health outcomes. Restricted cubic splines were used to evaluate possible linear or non-linear associations of total sedentary behaviour and television viewing with these health outcomes.

RESULTS

We included 48 articles (58 studies) with a total of 1 071 967 participants in the meta-analysis; 21 (six cohort and 15 cross-sectional) studies examined the association of total sedentary behaviour with overweight/obesity, 23 (13 cohort and 10 cross-sectional) studies examined the association with type 2 diabetes and 14 (one cohort and 13 cross-sectional) studies examined the association with hypertension. We found linear associations between total sedentary behaviour and type 2 diabetes (P_{non-linearity} = 0.190) and hypertension (P_{non-linearity} = 0.225) and a non-linear association between total sedentary behaviour and overweight/obesity (P_{non-linearity} = 0.003). For each 1-h/d increase in total sedentary behaviour, the risk increased by 5% for type 2 diabetes and 4% for hypertension. We also found linear associations between television viewing and type 2 diabetes (P_{non-linearity} = 0.948) and hypertension (P_{non-linearity} = 0.679) and a non-linear association for overweight/obesity (P_{non-linearity} = 0.007). For each 1-h/d increase in television viewing, the risk increased by 8% for type 2 diabetes and 6% for hypertension.

CONCLUSIONS

High levels of total sedentary behaviour and television viewing were associated with overweight/obesity, type 2 diabetes and hypertension.

Sedentary Behavior and Prevalent Diabetes in 6,166 Older Women: The Objective Physical Activity and Cardiovascular Health Study

BACKGROUND

We examined associations of sedentary time and sedentary accumulation patterns (ie, how sedentary time is accumulated) with prevalent diabetes in an ethnically diverse cohort of older women.

METHODS

Community-dwelling women aged 63-99 (n = 6,116; median age = 79) wore ActiGraph GT3X+ accelerometers 24 h/day for up to 7 days from which we derived average daily sedentary time and three measures of sedentary accumulation patterns: breaks in sedentary time, usual sedentary bout duration, and alpha. Odds ratios (ORs) and 95% confidence intervals (CIs) for prevalent diabetes were estimated using multivariable logistic regression.

RESULTS

Twenty-one percent (n = 1,282) of participants had diabetes. Women in the highest quartile of sedentary time (≥10.3 h/day) had higher odds of diabetes (OR = 2.18; 95% CI = 1.77-2.70) than women in the lowest quartile (≤8.3 h/day). Prolonged accumulation patterns (ie, accumulating sedentary time in longer sedentary bouts) was associated with higher odds of diabetes than regularly interrupted patterns (comparing quartiles with the most vs least prolonged patterns: usual bout duration OR = 1.57, 95% CI = 1.28-1.92; alpha OR = 1.61, 95% CI = 1.32-1.97); however, there was no significant association for breaks in sedentary time (OR = 1.00, 95% CI = 0.82-1.20).

CONCLUSIONS

High levels of sedentary time and accumulating it in prolonged patterns were associated with increased odds of diabetes among older women.

Association of Physical Activity and Fracture Risk Among Postmenopausal Women

Importance

Physical activity is inversely associated with hip fracture risk in older women. However, the association of physical activity with fracture at other sites and the role of sedentary behavior remain unclear.

Objective

To assess the associations of physical activity and sedentary behavior with fracture incidence among postmenopausal women.

Design, Setting, and Participants

The Women's Health Initiative prospective cohort study enrolled 77 206 postmenopausal women aged 50 to 79 years between October 1993 and December 1998 at 40 US clinical centers. Participants were observed for outcomes through September 2015, with data analysis conducted from June 2017 to August 2019.

Exposures

Self-reported physical activity and sedentary time.

Main Outcomes and Measures

Hazard ratios (HRs) and 95% CIs for total and site-specific fracture incidence.

Results

During a mean (SD) follow-up period of 14.0 (5.2) years among 77 206 women (mean [SD] age, 63.4 [7.3] years; 66 072 [85.6%] white), 25 516 (33.1%) reported a first incident fracture. Total physical activity was inversely associated with the multivariable-adjusted risk of hip fracture (>17.7 metabolic equivalent [MET] h/wk vs none: HR, 0.82; 95% CI, 0.72-0.95; P for trend < .001). Inverse associations with hip fracture were also observed for walking (>7.5 MET h/wk vs none: HR, 0.88; 95% CI, 0.78-0.98; P for trend = .01), mild activity (HR, 0.82; 95% CI, 0.73-0.93; P for trend = .003), moderate to vigorous activity (HR, 0.88; 95% CI, 0.81-0.96; P for trend = .002), and yard work (HR, 0.90; 95% CI, 0.82-0.99; P for trend = .04). Total activity was positively associated with knee fracture (>17.7 MET h/wk vs none: HR, 1.26; 95% CI, 1.05-1.50; P for trend = .08). Mild activity was associated with lower risks of clinical vertebral fracture (HR, 0.87; 95% CI, 0.78-0.96; P for trend = .006) and total fractures (HR, 0.91; 95% CI, 0.87-0.94; P for trend < .001). Moderate to vigorous activity was positively associated with wrist or forearm fracture (HR, 1.09; 95% CI, 1.03-1.15; P for trend = .004). After controlling for covariates and total physical activity, sedentary time was positively associated with total fracture risk (>9.5 h/d vs <6.5 h/d: HR, 1.04; 95% CI, 1.01-1.07; P for trend = .01). When analyzed jointly, higher total activity mitigated some of the total fracture risk associated with sedentary behavior. Analysis of time-varying exposures resulted in somewhat stronger associations for total physical activity, whereas those for sedentary time were materially unchanged.

Conclusions and Relevance

In older ambulatory women, higher total physical activity was associated with lower total and hip fracture risk but higher knee fracture risk. Mild activity and walking were associated with lower hip fracture risk, a finding with important public health implications because these activities are common in older adults. The positive association between sedentary time and total fracture risk requires further investigation.

Sitting Time and Risk of Cardiovascular Disease and Diabetes: A Systematic Review and Meta-Analysis

CONTEXT

Whether physical activity attenuates the association of total daily sitting time with cardiovascular disease and diabetes incidence is unclear. This systematic review and meta-analysis examined the association of total daily sitting time with cardiovascular disease and diabetes with and without adjustment for physical activity.

EVIDENCE ACQUISITION

PubMed, Web of Science, BASE, MEDLINE, Academic Search Elite, and ScienceDirect were searched for prospective studies, published between January 1, 1989, and February 15, 2019, examining the association of total daily sitting time with cardiovascular disease or diabetes outcomes. Data extraction and study quality assessments were conducted by 2 independent reviewers. Pooled hazard ratios (HRs) were calculated using a fixed-effects model. The quality assessment and meta-analysis procedures were completed in 2018.

EVIDENCE SYNTHESIS

Nine studies with 448,285 participants were included. A higher total daily sitting time was associated with a significantly increased risk of cardiovascular disease (HR=1.29, 95% CI=1.27, 1.30, p<0.001) and diabetes (HR=1.13, 95% CI=1.04, 1.22, p<0.001) incidence when not adjusted for physical activity. The increased risk for diabetes was unaffected when adjusting for physical activity (HR=1.11, 95% CI=1.01, 1.19, p<0.001). For cardiovascular disease, the increased risk was attenuated but remained significant (HR=1.14, 95% CI=1.04, 1.23, p<0.001).

CONCLUSIONS

Higher levels of total daily sitting time are associated with an increased risk of cardiovascular disease and diabetes, independent of physical activity. Reductions in total daily sitting may be recommended in public health guidelines.

The effects of cigarette smoking on the associations between sitting time and all-cause mortality: a meta-analysis

BACKGROUND

Sedentary behavior is recognized as an independent risk factor for mortality, but it remains unclear whether cigarette smoking will aggravate the detrimental effects of prolonged sitting on mortality. This study examined the impact of cigarette smoking on the relationship between sitting time and all-cause mortality in adults.

METHODS

Electronic database searches were conducted in PubMed, Web of Science, and the EMBASE up to 1 June 2017. Prospective studies that reported sitting time, percent of current smokers, and all-cause mortality were included. Data were extracted independently by two authors.

RESULTS

Ten prospective studies met the inclusion criteria. These studies included 850990 adults who were followed up for 2-15.7 years, during which 64 781 died (7.6%). Generally, during follow-up sitting time showed a dose-response relationship with all-cause mortality, with each 1 h increment of sitting time per day accounting for hazard ratio (HR) of mortality 1.02 (95%CI, 1.02-1.03). The relationship remained significant when stratified by the quartiles of smoking populations (≤8.4%, 8.5%-12.6%, 12.7%-27.9%, and ≥28.0%), and the risk of sitting time-related mortality increased parallel to the increment of the percent of smoking populations, with HRs 1.02 (95%CI, 1.02-1.03), 1.03 (95%CI, 1.02-1.03), 1.04 (95%CI, 1.03-1.04) and 1.06 (95%CI, 1.06-1.06), respectively. The associations between the risk of prolonged sitting-related mortality and the percent of smoking populations were linear (P = 0.032).

CONCLUSIONS

Cigarette smoking significantly aggravated the detrimental effects of sitting time on all-cause mortality. Our findings provided further evidence on the harmful effects of smoking combing prolonged sitting on adult health.

Sedentary behaviour and risk of all-cause, cardiovascular and cancer mortality, and incident type 2 diabetes: a systematic review and dose response meta-analysis

PURPOSE

 To estimate the strength and shape of the dose-response relationship between sedentary behaviour and all-cause, cardiovascular disease (CVD) and cancer mortality, and incident type 2 diabetes (T2D), adjusted for physical activity (PA). Data Sources: Pubmed, Web of Knowledge, Medline, Embase, Cochrane Library and Google Scholar (through September-2016); reference lists. Study Selection: Prospective studies reporting associations between total daily sedentary time or TV viewing time, and ≥ one outcome of interest. Data Extraction: Two independent reviewers extracted data, study quality was assessed; corresponding authors were approached where needed. Data Synthesis: Thirty-four studies (1,331,468 unique participants; good study quality) covering 8 exposure-outcome combinations were included. For total sedentary behaviour, the PA-adjusted relationship was non-linear for all-cause mortality (RR per 1 h/day: were 1.01 (1.00-1.01) ≤ 8 h/day; 1.04 (1.03-1.05) > 8 h/day of exposure), and for CVD mortality (1.01 (0.99-1.02) ≤ 6 h/day; 1.04 (1.03-1.04) > 6 h/day). The association was linear (1.01 (1.00-1.01)) with T2D and non-significant with cancer mortality. Stronger PA-adjusted associations were found for TV viewing (h/day); non-linear for all-cause mortality (1.03 (1.01-1.04) ≤ 3.5 h/day; 1.06 (1.05-1.08) > 3.5 h/day) and for CVD mortality (1.02 (0.99-1.04) ≤ 4 h/day; 1.08 (1.05-1.12) > 4 h/day). Associations with cancer mortality (1.03 (1.02-1.04)) and T2D were linear (1.09 (1.07-1.12)).

CONCLUSIONS

 Independent of PA, total sitting and TV viewing time are associated with greater risk for several major chronic disease outcomes. For all-cause and CVD mortality, a threshold of 6-8 h/day of total sitting and 3-4 h/day of TV viewing was identified, above which the risk is increased.

Lifestyle precision medicine: the next generation in type 2 diabetes prevention?

The driving force behind the current global type 2 diabetes epidemic is insulin resistance in overweight and obese individuals. Dietary factors, physical inactivity, and sedentary behaviors are the major modifiable risk factors for obesity. Nevertheless, many overweight/obese people do not develop diabetes and lifestyle interventions focused on weight loss and diabetes prevention are often ineffective. Traditionally, chronically elevated blood glucose concentrations have been the hallmark of diabetes; however, many individuals will either remain 'prediabetic' or regress to normoglycemia. Thus, there is a growing need for innovative strategies to tackle diabetes at scale. The emergence of biomarker technologies has allowed more targeted therapeutic strategies for diabetes prevention (precision medicine), though largely confined to pharmacotherapy. Unlike most drugs, lifestyle interventions often have systemic health-enhancing effects. Thus, the pursuance of lifestyle precision medicine in diabetes seems rational. Herein, we review the literature on lifestyle interventions and diabetes prevention, describing the biological systems that can be characterized at scale in human populations, linking them to lifestyle in diabetes, and consider some of the challenges impeding the clinical translation of lifestyle precision medicine.

Total sitting time and the risk of incident diabetes in Danish adults (the DANHES cohort) over 5 years: a prospective study

AIMS

To test the hypothesis that total sitting time is associated with incident diabetes, after adjustment for physical activity and obesity.

METHODS

72 608 Danish adults from the DANHES cohort reported their total sitting time in 2007-2008 and were followed-up for 5 years, in relation to register-based incident diabetes mellitus. Cox regression analyses were used, and the effect-modifying influence of obesity and physical activity assessed.

RESULTS

The age-sex adjusted HR for developing diabetes among those who sat 10+ h/day as compared to <6 h/day was 1.35 (95% CI 1.17 to 1.57). The relative risks were similar by gender, but were largely attenuated by adjustment for potential confounding factors including physical activity, and statistically non-significant for all categories of body mass index except the obese.

CONCLUSIONS

The association between total sitting time and incident diabetes is substantially moderated by physical activity and obesity. Total sitting time remains a risk factor for diabetes only in inactive and obese populations.

Independent and combined effects of physical activity and body mass index on the development of Type 2 Diabetes - a meta-analysis of 9 prospective cohort studies

Background

The aim of this harmonized meta-analysis was to examine the independent and combined effects of physical activity and BMI on the incidence of type 2 diabetes.

Methods

Our systematic literature review in 2011 identified 127 potentially relevant prospective studies of which 9 fulfilled the inclusion criteria (total N = 117,878, 56.2 % female, mean age = 50.0 years, range = 25–65 years). Measures of baseline physical activity (low, intermediate, high), BMI-category [BMI < 18.4 (underweight), 18.5–24.9 (normal weight), 25.0–29.9 (overweight), 30+ (obese)] and incident type 2 diabetes were harmonized across studies. The associations between physical activity, BMI and incident type 2 diabetes were analyzed using Cox regression with a standardized analysis protocol including adjustments for age, gender, educational level, and smoking. Hazard ratios from individual studies were combined in a random-effects meta-analysis.

Results

Mean follow-up time was 9.1 years. A total of 11,237 incident type 2 diabetes cases were recorded. In mutually adjusted models, being overweight or obese (compared with normal weight) and having low physical activity (compared with high physical activity) were associated with an increased risk of incident type 2 diabetes (hazard ratios 2.33, 95 % CI 1.95–2.78; 6.10, 95 % CI: 4.63–8.04, and 1.23, 95 % CI: 1.09–1.39, respectively). Individuals who were both obese and had low physical activity had 7.4-fold (95 % CI 3.47–15.89) increased risk of type 2 diabetes compared with normal weight, high physically active participants.

Conclusions

This harmonized meta-analysis shows the importance of maintaining a healthy weight and being physically active in diabetes prevention.

Electronic supplementary material

The online version of this article (doi:10.1186/s12966-015-0304-3) contains supplementary material, which is available to authorized users.

Nonexercise activity thermogenesis in obesity management

Obesity is linked to cardiovascular disease. The global increase in sedentary lifestyle is an important factor contributing to the rising prevalence of the obesity epidemic. Traditionally, counseling has focused on moderate- to vigorous-intensity exercise, with disappointing results. Nonexercise activity thermogenesis (NEAT) is an important component of daily energy expenditure. It represents the common daily activities, such as fidgeting, walking, and standing. These high-effect NEAT movements could result in up to an extra 2000 kcal of expenditure per day beyond the basal metabolic rate, depending on body weight and level of activity. Implementing NEAT during leisure-time and occupational activities could be essential to maintaining a negative energy balance. NEAT can be applied by being upright, ambulating, and redesigning workplace and leisure-time environments to promote NEAT. The benefits of NEAT include not only the extra calories expended but also the reduced occurrence of the metabolic syndrome, cardiovascular events, and all-cause mortality. We believe that to overcome the obesity epidemic and its adverse cardiovascular consequences, NEAT should be part of the current medical recommendations. The content of this review is based on a literature search of PubMed and the Google search engine between January 1, 1960, and October 1, 2014, using the search terms physical activity, obesity, energy expenditure, nonexercise activity thermogenesis, and NEAT.