Human adaptation to cold and warm climatic conditions: A comparison between two geographically diverse Indigenous populations

OBJECTIVES

The present study aims to compare body adiposity and blood pressure (BP) in two climatically and ethnically diverse populations, examining whether thermoregulatory adaptive mechanism may protect Indigenous populations from exhibiting adverse consequences of increased adiposity.

METHODS

A cross sectional sample of 404 subjects, of which 200 were Monpa and 204 were Santhal, from two ethnically and geographically distinct populations of India were studied. Body mass index (BMI; kg/m2 ), fat mass (FM; kg), fat free mass (kg), and percent body fat (%BF) were calculated for evaluation of body adiposity. Multivariate multiple regression analysis was adopted to examine the influence of age and sex of populations under study, on body adiposity and BP variables.

RESULTS

BMI, %BF, and FM were found to be significantly higher (p ˂ .001) among the Monpa males and females compared with their Santhal counterparts. In contrast, the prevalence of hypertension among Monpa and Santhal is comparable (3.5%Monpa vs. 3.9%Santhal for systolic BP; 8.5%Monpa vs. 8.3%Santhal for diastolic BP). Adiposity, as quantitated by the fat mass index and %BF was significantly (p ˂ .001) correlated to age and sex of study population, explaining ~75.3% and ~75.4% of total variations of these variables, respectively.

CONCLUSIONS

Overall the present study suggests that modern human populations follow thermoregulatory mechanism for adaptation to different climatic conditions. Consequently, greater adiposity was evident among the Monpa who adapt to the cold climate, in comparison to their Santhal counterparts who dwell in warm climate.

Surrogate Markers of Cardiovascular Risk and Chronic Obstructive Pulmonary Disease: A Large Case-Controlled Study

Cardiovascular disease is a common comorbidity and cause of mortality in chronic obstructive pulmonary disease. A better understanding of mechanisms of cardiovascular risk in chronic obstructive pulmonary disease patients is needed to improve clinical outcomes. We hypothesized that such patients have increased arterial stiffness, wave reflections, and subclinical atherosclerosis compared with controls and that these findings would be independent of smoking status and other confounding factors. A total of 458 patients with a diagnosis of chronic obstructive pulmonary disease and 1657 controls (43% were current or ex-smokers) with no airflow limitation were matched for age, sex, and body mass index. All individuals underwent assessments of carotid-femoral (aortic) pulse wave velocity, augmentation index, and carotid intima-media thickness. The mean age of the cohort was 67±8 years and 58% were men. Patients with chronic obstructive pulmonary disease had increased aortic pulse wave velocity (9.95±2.54 versus 9.27±2.41 m/s; P<0.001), augmentation index (28±10% versus 25±10%; P<0.001), and carotid intima-media thickness (0.83±0.19 versus 0.74±0.14 mm; P<0.001) compared with controls. Chronic obstructive pulmonary disease was associated with increased levels of each vascular biomarker independently of physiological confounders, smoking, and other cardiovascular risk factors. In this large case-controlled study, chronic obstructive pulmonary disease was associated with increased arterial stiffness, wave reflections, and subclinical atherosclerosis, independently of traditional cardiovascular risk factors. These findings suggest that the cardiovascular burden observed in this condition may be mediated through these mechanisms and supports the concept that chronic obstructive pulmonary disease is an independent risk factor for cardiovascular disease.

Physical activity level significantly affects the survival of patients with end-stage lung disease on a waiting list for lung transplantation

PURPOSE

Our objective was to investigate the factors predicting the survival of patients on the waiting list for lung transplantation (LT) during the waiting period, with a special emphasis on the physical activity level.

METHODS

The study included 70 patients with end-stage pulmonary disease who were on the waiting list for LT at Kyoto University Hospital. We examined the association between the baseline characteristics, including the body mass index and body composition, serum albumin, serum C-reactive protein (CRP), steroid administration, physical activity level (calculated by the food frequency questionnaire) and survival during the waiting period using Kaplan-Meier curves and Cox proportional hazard regression models.

RESULTS

A physical activity level of ≤1.2 was correlated with significantly decreased survival (1-year survival: 68 vs. 90.9%, p = 0.0089), with a hazard ratio (HR) of 2.24 (95% confidence interval (CI) 1.22-4.19, p = 0.0001). Hypo-albumin (HR 2.024, 95% CI 1.339-6.009, p = 0.004), a high level of CRP (HR 2.551, CI 1.229-4.892, p = 0.02), and the administration of steroids (HR 2.258, CI 1.907-5.032, p = 0.024) were also significant predictors of survival.

CONCLUSIONS

Low levels of physical activity during the waiting period for LT led to decreased survival times among LT candidates.