Aims

Previous characterisation of body composition as a type 2 diabetes mellitus (T2DM) risk factor has largely focused on adiposity, but less is known about the independent role of skeletal muscle. We examined associations between abdominal muscle and measures of glucose regulation.

Materials and methods

Cross-sectional analysis of 1,891 adults enrolled in the Multi-Ethnic Study of Atherosclerosis. Multivariable regression assessed associations between abdominal muscle area and density (measured by computed tomography) with fasting glucose, homeostasis model assessment of insulin resistance (HOMA-IR), and prevalent T2DM (fasting glucose ≥126 mg/dL or medication use).

Results

In minimally adjusted models (age, sex, race/ethnicity, income), a 1-SD increment in abdominal muscle area was associated with higher HOMA-IR (β = 0.20 ± SE 0.03; 95%CI: 0.15, 0.25; P < 0.01) and odds of T2DM (OR = 1.47; 95%CI: 1.18, 1.84; P < 0.01), while higher density was associated with lower fasting glucose (-4.49 ± 0.90; -6.26, -2.72; P < 0.01), HOMA-IR (-0.16 ± 0.02; -0.20, -0.12; P < 0.01), and odds of T2DM (0.64; 0.52, 0.77; P < 0.01). All associations persisted after adjustment for comorbidities and health behaviours. However, after controlling for height, BMI, and visceral adiposity, increasing muscle area became negatively associated with fasting glucose (-2.23 ± 1.01; -4.22, -0.24; P = 0.03), while density became positively associated with HOMA-IR (0.09 ± 0.02; 0.05, 0.13; P < 0.01).

Conclusions

Increasing muscle density was associated with salutary markers of glucose regulation, but associations inverted with further adjustment for body size and visceral adiposity. Conversely, after full adjustment, increasing muscle area was associated with lower fasting glucose, suggesting some patients may benefit from muscle-building interventions.

Background

Travel time to treatment facilities may impede the receipt of guideline-concordant treatment (GCT) among patients diagnosed with early-stage non-small cell lung cancer (ES-NSCLC). We investigated the relative contribution of travel time in the receipt of GCT among ES-NSCLC patients.

Methods

We included 22,821 ES-NSCLC patients diagnosed in California from 2006-2015. GCT was defined using the 2016 National Comprehensive Cancer Network guidelines, and delayed treatment was defined as treatment initiation >6 versus ≤6 weeks after diagnosis. Mean-centered driving and public transit times were calculated from patients' residential block group centroid to the treatment facilities. We used logistic regression to estimate risk ratios and 95% confidence intervals (CIs) for the associations between patients' travel time and receipt of GCT and timely treatment, overall and by race/ethnicity and neighborhood socioeconomic status (nSES).

Results

Overall, a 15-minute increase in travel time was associated with a decreased risk of undertreatment and delayed treatment. Compared to Whites, among Blacks, a 15-minute increase in driving time was associated with a 24% (95%CI = 8%-42%) increased risk of undertreatment, and among Filipinos, a 15-minute increase in public transit time was associated with a 27% (95%CI = 13%-42%) increased risk of delayed treatment. Compared to the highest nSES, among the lowest nSES, 15-minute increases in driving and public transit times were associated with 33% (95%CI = 16%-52%) and 27% (95%CI = 16%-39%) increases in the risk of undertreatment and delayed treatment, respectively.

Conclusion

The benefit of GCT observed with increased travel times may be a 'Travel Time Paradox,' and may vary across racial/ethnic and socioeconomic groups.

Aims

Type 2 diabetes mellitus (T2DM) and visceral obesity are associated with each other and with cardiovascular diseases. We determined whether increased visceral adiposity without weight gain was associated with sex-specific accelerated carotid atherosclerosis in South Koreans with T2DM.

Methods

From 2003 to 2012, we recruited 280 participants with T2DM for the Seoul Metabolic Syndrome cohort who had body weight, visceral fat thickness (VFT), and carotid intima-media thickness (CIMT) measured at intervals of 2years. According to VFT change, sex-specific quartiles of clinical characteristics and changes of CIMT were determined. Logistic regression models predicted the odds of the progression of CIMTs in each quartile.

Results

During 2years of observation, VFTs fell by 5.2±13.5mm in men (P<0.001) and 3.4±10.5mm in women (P<0.001). Progression of CIMT was only significant for women's maximal CIMT (0.031±0.145mm, P=0.012), while significant improvements in HbA1c were found (0.9%; P<0.001 in both sexes). There were no significant differences in clinical characteristics, or in progression of CIMT in men or women according to 2-year quartiles of VFT change.

Conclusions

Our results do not suggest that increased visceral adiposity without body weight changes impacts the CIMT progression in South Korean men or women with T2DM.

Objective

To examine the association of abdominal muscle area with coronary artery calcium (CAC) presence, extent, and progression in a multi-ethnic cohort of older, community-dwelling post-menopausal women.

Design and setting

Cross-sectional and longitudinal population-based cohort.

Participants

The sample comprised 179 non-Hispanic White women, 116 Filipina women and 144 African American women, all without known CVD, who underwent chest and abdominal computed tomography (CT) scans twice about four years apart for abdominal muscle and fat, as well as CAC.

Main outcome measures

CAC presence, extent and progression.

Results

There was a significant interaction of ethnicity with baseline oblique muscle area (p-for-interaction .01), and marginally significant interactions with baseline total and paraspinal muscle for change in CAC (p-for-interactions both .09). Among Filipina women, each standard deviation (SD) greater total muscle area was associated with a 26% (95% CI (-43%, -4%), P=.02) reduced rate of change in CAC; higher paraspinal and oblique muscle area were associated with a 24% (-38%, -6%, P=.01) and a 37% (-53%, -16%, P=.0002) reduced rate of change in CAC, respectively. These associations were not significant in African American or non-Hispanic White women. There were no significant associations of abdominal muscle with CAC presence or extent, nor were there significant ethnicity by muscle interactions in these models.

Conclusions

Among Filipina women, greater abdominal muscle mass is associated with a decreased rate of CAC progression. Higher muscle mass may be important for this group in reducing CVD outcomes.

Objective

We examined the association between breastfeeding and postmenopausal visceral adiposity.

Methods

Participants were community-dwelling women aged 55-80 from the Caucasian Rancho Bernardo Study, the Filipino Women's Health Study, and the Health Assessment Study of African-American Women who had visceral adipose tissue (VAT) measurements by computed tomography between 2000 and 2002. Linear regression was used to determine the association between average breastfeeding duration per child and VAT.

Results

In Caucasian, Filipino, and African-American women, average number of live births was 3, 4, and 3; average breastfeeding duration was 4.3, 1.8, and 5.1 months, respectively. Filipino women had more live births, were more likely to breastfeed, and breastfed shorter durations. African-American women had lower VAT, despite higher subcutaneous adipose tissue (SAT), BMI, and waist girth. Women who breastfed >3 months on average had 8.8 cm(3) lower VAT than women who breastfed ≤3 months, independent of covariates. Women who initiated breastfeeding had lower BMI and waist girth than those who did not, but they did not differ by VAT unless they breastfed >3 months. Associations were independent of race/ethnicity.

Conclusions

Results suggest breastfeeding initiation is associated with reduced BMI and smaller waist girth, and breastfeeding >3 months is associated with lower postmenopausal VAT.

Introduction

Increased sedentary behavior predicts greater cardiovascular morbidity and mortality and does so independently of physical activity (PA). This association is only partially explained by body mass index (BMI) and overall body fat, suggesting mechanisms besides general increased adiposity. The purpose of this study was to explore associations of self-reported leisure PA and sitting time with regional fat depositions and abdominal muscle among community-dwelling older adults.

Methods

Participants were 539 diverse adults (mean age = 65 yr) who completed a study visit in 2001-2002. Areas of pericardial, intrathoracic, subcutaneous, visceral, and intermuscular fat, as well as abdominal muscle, were measured using computed tomography. Leisure PA and sitting hours were entered simultaneously into multivariate regression models to determine associations with muscle and fat areas.

Results

After adjusting for demographics, smoking, diabetes, hypertension, triglycerides, and cholesterol, greater PA was associated with less intrathoracic, visceral, subcutaneous, and intermuscular fat (for all P < 0.05), while greater sedentary time was associated with greater pericardial and intrathoracic fat (for both P < 0.05). After further adjusting for BMI, each hour of weekly PA was associated with 1.85 cm less visceral fat (P < 0.01) but was not associated with other fat depositions. Conversely, each hour of daily sitting was associated with 2.39 cm more pericardial fat (P < 0.05) but was not associated with any other fat depositions. There were no associations with abdominal muscle area. Adjusting for common inflammatory markers had little effect. Associations between fat and PA were stronger for men.

Conclusions

Sitting and PA have distinct associations with regional fat deposition in older adults. The association between sitting and pericardial fat could partially explain the link between sitting and coronary heart disease.

Every year billions of chickens are shipped thousands of miles around the globe in order to meet the ever increasing demands for this cheap and nutritious protein source. Unfortunately, transporting chickens internationally can also increase the chance for introducing zoonotic viruses, such as highly pathogenic avian influenza A (H5N1) to new countries. Our study used a retrospective analysis of poultry trading data from 2003 through 2011 to assess the risk of H5N1 poultry infection in an importing country. We found that the risk of infection in an importing country increased by a factor of 1.3 (95% CI: 1.1-1.5) for every 10-fold increase in live chickens imported from countries experiencing at least one H5N1 poultry case during that year. These results suggest that the risk in a particular country can be significantly reduced if imports from countries experiencing an outbreak are decreased during the year of infection or if biosecurity measures such as screening, vaccination, and infection control practices are increased. These findings show that limiting trade of live chickens or increasing infection control practices during contagious periods may be an important step in reducing the spread of H5N1 and other emerging avian influenza viruses.

Using data from the Multi-Ethnic Study of Atherosclerosis (United States, 2000-2015), 6,527 racially/ethnically diverse adults (mean age, 62 (standard deviation, 10) years) free of known cardiovascular (CVD) had ankle brachial index (ABI) assessment of their bilateral dorsalis pedis/posterior tibial arteries (4 vessels total) and were followed for total mortality and incident CVD events/mortality. Individuals were classified into categories of 0-, 1-, 2-, 3- or 4-vessel peripheral artery disease (PAD) (ABI of ≤0.9). There were 1,202 deaths (18%), 656 incident CVD events (10%), and 282 CVD deaths (4.3%). Of the 6,527 individuals, 5,711 (87.5%) had 0-, 460 (7.0%) had 1-, 218 (3.3%) had 2-, 69 (1.1%) had 3-, and 69 (1.1%) had 4-vessel PAD, respectively. In multivariable Cox models, higher number of vessels with PAD was associated with higher risk of mortality (P for trend <0.001), CVD events (P for trend = 0.002), and CVD mortality (P for trend = 0.001). Compared with individuals who had 0-vessel disease, hazard ratios for mortality were 1.29 (95% confidence interval (CI): 1.06, 1.59) for 1-, 1.45 (95% CI: 1.14, 1.86) for 2-, 1.58 (95% CI: 1.13, 2.21) for 3-, and 2.15 (95% CI: 1.58, 2.94) for 4-vessel disease. A similar pattern was seen for CVD events/mortality. These results suggest the importance of accounting for ABI values of all 4 leg arteries in clinical practice and research.

Background

The association between sugar-sweetened beverage (SSB) consumption and colorectal cancer (CRC) risk remains unclear and published data are limited.

Methods

The analytic cohort included 99,798 women, free of cancer at baseline, from the California Teachers Study, a longitudinal cohort comprised of 133,477 female teachers and administrators who were active or recently retired members of the California State Teachers Retirement System in 1995. SSB consumption constituted caloric soft drinks, sweetened bottled waters and teas, and fruit drinks, derived from a self-administered food frequency questionnaire. Consumption was divided into four categories: Rare or never, >rare/never to <1 serving/week, ≥1 serving/week to <1 serving/day, and ≥1 serving/day. CRC endpoints were based on annual linkage with California Cancer Registry, defined as first diagnosis of CRC, and classified following the Surveillance, Epidemiology, and End Results Program coding system. Multivariable-adjusted Cox proportional hazards models were used to generate hazard ratios (HR) and 95% confidence intervals (CI) for assessing the association between SSB consumption and incident CRC.

Results

A total of 1,318 incident CRC cases were identified over 20 years of follow-up (54.5% proximal colon and 45.5% distal colorectum). Compared with rare/never consumers, the multivariable-adjusted HRs (95% CI) were 1.14 (0.86, 1.53) for total CRC; 1.11 (0.73, 1.68) for proximal colon; and 1.22 (0.80, 1.86) for distal colorectum cancers among women consuming ≥ 1 serving/day of SSBs.

Conclusion

SSBs were not significantly associated with CRC risk. The biological effects of high SSB consumption make it important to continue to evaluate whether SSBs are associated with CRC. Additionally, future studies should further assess SSBs in large, racial/ethnically diverse cohorts of males and females, and, if feasible, address changes in SSB consumption over time.

Purpose

Chronic stimulation and dysregulation of the neuroendocrine system by stress may cause metabolic abnormalities. We estimated how much cortisol and psychosocial outcomes improved with a restorative yoga (relaxation) versus a low impact stretching intervention for individuals with the metabolic syndrome.

Methods

We conducted a 1-year multi-center randomized controlled trial (6-month intervention and 6-month maintenance phase) of restorative yoga vs. stretching. Participants completed surveys to assess depression, social support, positive affect, and stress at baseline, 6 months and 12 months. For each assessment, we collected saliva at four points daily for three days and collected response to dexamethasone on the fourth day for analysis of diurnal cortisol dynamics. We analyzed our data using multivariate regression models, controlling for study site, medications (antidepressants, hormone therapy), body mass index, and baseline cortisol values.

Results

Psychosocial outcome measures were available for 171 study participants at baseline, 140 at 6 months, and 132 at 1 year. Complete cortisol data were available for 136 of 171 study participants (72 in restorative yoga and 64 in stretching) and were only available at baseline and 6 months. At 6 months, the stretching group had decreased cortisol at waking and bedtime compared to the restorative yoga group. The pattern of changes in stress mirrored this improvement, with the stretching group showing reductions in chronic stress severity and perseverative thoughts about their stress. Perceived stress decreased by 1.5 points (-0.4; 3.3, p=0.11) at 6 months, and by 2.0 points (0.1; 3.9, p=0.04) at 1 year in the stretching compared to restorative yoga groups. Post hoc analyses suggest that in the stretching group only, perceived increases in social support (particularly feelings of belonging), but not changes in stress were related to improved cortisol dynamics.

Conclusions

We found significant decreases in salivary cortisol, chronic stress severity, and stress perception in the stretching group compared to the restorative yoga group. Group support during the interactive stretch classes may have contributed to these changes.