Effects of age on body temperature and blood pressure in cold environments

Short-term effect of apparent temperature on daily hospitalizations for osteoporotic fractures in Beijing, China: A retrospective observational study

BACKGROUND

Studies on the associations between temperature and osteoporotic fractures (OF) hospitalizations are limited. This study aimed to assess the short-term effect of apparent temperature (AT) on the risk of OF hospitalizations.

METHODS

This retrospective observational study was conducted in Beijing Jishuitan Hospital from 2004 to 2021. Daily OF hospitalizations, meteorological variables and fine particulate matter were collected. A Poisson generalized linear regression model combined with a distributed lag non-linear model was applied to analyze the lag-exposure-response relationship between AT and the number of OF hospitalizations. Subgroup analysis by gender, age and fracture type was also conducted.

RESULTS

Total daily hospitalization visits for OF during the studied period were 35,595. The exposure-response curve of AT and OF presented a non-linear relationship, with optimum apparent temperature (OAT) at 28.40 °C. Taking OAT as the reference, the cold effect (-10.58 °C, 2.5th percentage) on single lag day had statistical significance from the current day of exposure (RR = 1.18, 95 % CI: 1.08-1.28) to lag 4 day (RR = 1.04, 95 % CI: 1.01-1.08), while the cumulative cold effect increased the risk of OF hospitalization visits from lag 0 to 14 days, with the maximum RR over lag 0-14 days (RR = 1.84, 95 % CI: 1.21-2.79). There were no significant risks of OF hospitalizations for warm effects (32.53 °C, 97.5th percentage) on single or cumulative lag days. The cold effect might be more evident among females, patients aged 80 years or older, and patients with hip fractures.

CONCLUSION

Exposure to cold temperatures is associated with an increased risk of OF hospitalizations. Females, patients aged 80 years or older and patients with hip fractures might be more vulnerable to the cold effect of AT.

Associations between Frailty and Ambient Temperature in Winter: Findings from a Population-Based Study

Frailty is an accumulation of deficits characterized by reduced resistance to stressors and increased vulnerability to adverse outcomes. However, there is little known about the effect of ambient temperature in winter on frailty among older adults, a population segment with the highest frailty prevalence. Thus, the objective of this study is to investigate the associations between frailty and ambient temperature in winter among older adults. This study was based on the Chinese Longitudinal Healthy Longevity Survey (CLHLS) of older adults aged ≥65 years from the 2005, 2008, 2011, and 2014 waves. The 39-item accumulation of frailty index (FI) was used to assess the frailty status of the participants. The FI was categorized into three groups as follows: robust (FI ≤ 0.10), prefrail (FI > 0.10 to <0.25), and frail (FI ≥ 0.25). Generalized linear mixed models (GLMMs) were conducted to explore the associations between frailty and ambient temperature in winter. A generalized estimating equation (GEE) modification was applied in the sensitivity analysis. A total of 9421 participants were included with a mean age of 82.81 (SD: 11.32) years. Compared with respondents living in the highest quartile (≥7.5 °C) of average temperature in January, those in the lowest quartile (<−1.9 °C) had higher odds of prefrailty (OR = 1.35, 95% CI 1.17−1.57) and frailty (OR = 1.61, 95%CI 1.32−1.95). The associations were stronger among the low-education groups, agricultural workers before retirement, and non-current exercisers. Additionally, results from the GEE model reported consistent findings. Lower levels of ambient temperature in winter were associated with higher likelihoods of prefrailty and frailty. The findings on vulnerability characteristics could help improve public health practices to tailor cold temperature health education and warning information.

Is Cold Apparent Temperature Associated With the Hospitalizations for Osteoporotic Fractures in the Central Areas of Wuhan? A Time-Series Study

Osteoporosis is alarming problem due to aggravation of global aging, especially in China. Osteoporotic fracture (OF) is one of the most severe consequents of osteoporosis. Many previous studies found that environmental factors had adverse effects on human health. Cold temperature was associated with OF and bone metabolism in prior observational and experimental researches. However, few studies had been conducted on the acute effect of low temperature and OF. Data on daily meteorological factors and hospitalizations for OF were collected from Wuhan, China, between January 1, 2017 to December 24, 2019. Apparent temperature (AT), comprehensively considered a variety of environmental factors, was calculated by ambient temperature, relative humidity and wind speed. A generalized linear regression model combined with distributed lag non-linear regression model (DLNM) with quasi-Poisson link was used to explore the association between AT and the number of hospitalizations for OF. Subgroup analyses stratified by gender, age and the history of fracture were applied for detecting susceptible people. The exposure-response curve of AT and OF were generally U-shaped with lowest point at 25.8°C. The significant relationship of AT-OF existed only in cold effect (-2.0 vs. 25.8°C) while not in warm effect (37.0 vs. 25.8°C). Statistically significant risks of OF for cold effects were only found in females [RR = 1.12 (95%CI: 1.02, 1.24) at lag 2 day], aged <75 years old [RR = 1.18 (95%CI: 1.04, 1.33) and 1.17 (95%CI: 1.04, 1.33) at lag 2 and 3 days, respectively] and people with history of fracture [RR = 1.39 (95%CI: 1.02, 1.90) and 1.27 (95%CI: 1.05, 1.53) at lag 1 and 2 days, respectively]. The significant associations of AT on OF were only found in cold effect. The females, people aged <75 years and people with history of fracture possibly appeared to be more vulnerable. Public health departments should pay attention to the negative effect of cold AT and take measures in time.

A review of Japanese-style bathing: its demerits and merits

Japanese-style bathing (JSB), which involves soaking in hot water up to the shoulders in deep bathtubs for a long time in the evening to night, is unique. Many experimental and epidemiological studies and surveys have shown that JSB improve sleep quality, especially shortens sleep onset latency in winter. In addition, repeated JSB lead the improvement of depressive symptoms. JSB is a simple and low-cost non-pharmacological measure to sleep difficulty in winter and mental disorders, especially for the elderly. On the contrary, drowning, while soaking in a bathtub, is the most common of accidental death at home in Japan. It is estimated that approximately 19,000 Japanese individuals die annually while taking a bath, mostly during winter, and most victims are elderly people. Elderly Japanese people tend to prefer a higher-risk JSB because the temperature inside the house during winter, especially the dressing room/bathroom temperature, is very low. Since the physiological thermal effect of the elderly associated with bathing is relatively lower among the elderly than the young, the elderly prefer to take a long hot bath. This elderly’s favorite style of JSB results in larger increased blood pressure in dressing rooms and larger decreased in blood pressure during hot bathing. A sudden drop in blood pressure while immersed in the bathtub leads to fainting and drowning. Furthermore, elderly people are less sensitive to cold air or hot water, therefore, it is difficult to take appropriate measures to prevent large fluctuations in blood pressure. To ensure a safe and comfortable winter bathing, the dressing room/bathroom temperature needs to be maintained at 20 °C or higher, and several degrees higher would be recommended for the elderly.

Effects of body geometry, body composition, cardio-pulmonary capacity, and fitness on young men's thermal preference

This paper investigated principal parameters affecting individual differences of thermal preference. 36 male college students were selected from three thermal preference groups by a questionnaire, including 10 of cool preference (Gcp), 17 of neutral preference (Gnp), and 9 of warm preference (Gwp). Subsequently, their thermal preferences were further examined by a human trial in a climate chamber. Once significant differences were found between groups, subjects' 57 parameters, including body geometry, body composition, cardio-pulmonary capacity, and physical fitness, were measured. Compared to Gwp, Gcp had higher weight (80.0 vs. 64.2 kg), body mass index (BMI) (26 vs. 20.8 kg·m^-2 ), body surface area (BSA) (1.94 vs. 1.78 m² ), waist-to-hip ratio (WHR) (87.29% vs. 80.23%), body circumferences (except for forearm circumference), skinfold thickness of all the local parts, volume of expired air (VE) (50.97 vs. 40.81 L/min), and body fat rate (BFR) (24.44% vs. 14.07%), but had a lower specific surface area (SSA) (0.02477 vs. 0.02791 m² /kg), resting metabolic rate (RMR) per kilogram (1.21 vs. 1.47 W/kg), diastolic blood pressure (DBP) (65.30 vs. 74.69 mmHg), and percentages of muscle (71.17% vs. 80.95%), total water (55.35% vs. 63.14%), skeletal muscle (42.47% vs. 47.94%), protein (14.90% vs. 16.94%), inorganic salt (5.29% vs. 5.86%), and bone mineral (0.044% vs. 0.048%). Among these parameters, body fat and SSA played a dominant role (accounting for 85.76%) in explaining individual differences in thermal preference.

Effect of Laboratory Mental Stressors on Cardiovascular Reactivity in Young Women During Different Phases of Menstrual Cycle: An Observational Study

Introduction: Excessive cardiovascular reactivity to mental stress may be a risk factor for cardiovascular disease. However, there is inconsistent report in the literature regarding change in cardiac autonomic tone with the phase of the menstrual cycle and how it is affected by mental stress. Therefore, the present study was aimed at determining the cardiovascular reactivity to different laboratory mental stressors during follicular and luteal phase of menstrual cycle using heart rate variability (HRV). Methods: Thirty-three regularly cycling young females (19-35 years of age) were exposed to four cognitive tasks (Stroop test, Mental Rotation test, n-back test, and Mental Arithmetic Stress Test [MAST]) employed as laboratory mental stressors. HRV of the study participants were recorded before, during, and after each cognitive task and the recording was done in both phases of menstrual cycle for each individual. Results: A significant difference was observed in time domain parameters and nonlinear parameters of HRV in pretest versus during-test condition and during-test versus post-test conditions, but not in frequency domain parameters. No phase difference was found in time domain or frequency domain analysis of HRV in baseline or during performance of task. MAST performance (score out of 50) was significantly higher in luteal than follicular phase, while other tests showed no such difference. Conclusion: All four mental stress tasks used in the present study were able to elicit significant decrease in parasympathetic tone during performance of task as compared with baseline values of HRV. The present study did not elicit any phase difference in cardiovascular reactivity.

Effect of meteorological factors and air pollutants on fractures: a nationwide population-based ecological study

OBJECTIVE

To determine the association of meteorological factors and air pollutants (MFAPs) with fracture and to estimate the effect size/time lag.

DESIGN

This is a nationwide population-based ecological study from 2008 to 2017.

SETTING

Eight large metropolitan areas in Korea.

PARTICIPANTS

Of 8 093 820 patients with fractures reported in the Korea National Health Insurance database, 2 129 955 were analysed after the data set containing patient data (age, sex and site of fractures) were merged with MFAPs. Data on meteorological factors were obtained from the National Climate Data Center of the Korea Meteorological Administration. Additionally, data on air pollutants (atmospheric particulate matter ≤2.5 µm in diameter (PM_2.5), PM₁₀, ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide) were obtained from the Air Korea database.

PRIMARY AND SECONDARY OUTCOME MEASURES

We hypothesised that there would be an association between MFAPs and the incidence of fracture. A generalised additive model was used while factoring in the non-linear relationship between MFAPs and fractures as well as a time lag ≤7 days. Multivariate analysis was performed. Backward elimination with an Akaike information criterion was used to fit the multivariate model.

RESULTS

Overall, in eight urban areas, 2 129 955 patients with fractures were finally analysed. These included 370 344, 187 370, 173 100, 140 358, 246 775, 6501, 228 346, 57 183 and 719 978 patients with hip, knee, shoulder, elbow, wrist, hand, ankle, foot and spine fractures, respectively. Various MFAPs (average temperature, daily rain, wind speed, daily snow and PM_2.5) showed significant association with fractures, with positive correlations at time lags 7, 5-7, 5-7, 3-7 and 6-7 days, respectively.

CONCLUSIONS

Various MFAPs could affect the occurrence of fractures. The average temperature, daily rain, wind speed, daily snow and PM_2.5 were most closely associated with fracture. Thus, improved public awareness on these MFAPs is required for clinical prevention and management of fractures.

Seasonality of stroke: Winter admissions and mortality excess: A Thailand National Stroke population database study

OBJECTIVES

We examined the existence and potential burden of seasonality of stroke admissions and mortality within a tropical climate using cohort data collected between 1 st November 2003 and 31 st October 2012.

PATIENTS AND METHODS

In a prospective cohort of hospitalised stroke patients from the catchment of ∼75 % of the Thai population (n = 569,307; mean SD age = 64(14.5)), incident stroke admissions, in-hospital mortality, prolonged hospitalisations, and stroke related complications by season were determined. Rates of incident stroke admissions by month and season were plotted. Winter excess indexes for study outcomes expressed as a percentage were calculated. Using logistic regression we examined the association between winter admission and in-hospital mortality (non-winter admission as reference) adjusting for age, sex, stroke type, year of admission, and presence of pre-existing comorbidities.

RESULTS

We observed a winter excess in mortality during hospitalisation (+10.3 %) and prolonged length of stay (+7.3 %). Respective winter excess indexes for dyslipidaemias, arrhythmias, anaemia, and alcohol related disorders in patients that died during hospitalisation were +1.4 %, +6.2 %, +0.2 %, +1.5 %. In these patients, respective winter excess indexes for post-stroke complications of pneumonia and sepsis were +6.7 % and +3.2 %. In fully adjusted analyses, winter admission (compared to non-winter admission) was associated with increased odds of in-hospital mortality (OR (95 % CI) = 1.023 (1.006-1.040)).

CONCLUSIONS

We provide robust evidence for the existence of an excess in winter stroke admissions and subsequent in-hospital deaths within a tropical region.

Risk of Out-of-Hospital Cardiac Arrest in Aged Individuals in Relation to Cold Ambient Temperature - A Report From North Tochigi Experience

BACKGROUND

The impact of cold ambient temperature on out-of-hospital cardiac arrest (OHCA) in aged individuals caused by cardiovascular events in indoor environments has not been investigated sufficiently.Methods and Results:We conducted a case-crossover study. The relationship between OHCA caused by cardiovascular events and exposure to minimum temperature <0℃ was analyzed. Conditional logistic regression analysis was performed to estimate the odds ratios for the relationship between exposure to minimum temperature <0℃ and the risk of OHCA. Between January 1, 2011, and December 31, 2015, a total of 1,452 cases of OHCA were documented, and patients were screened for enrollment. A total of 458 individuals were enrolled in this analysis, and were divided into 2 groups of 110 (elderly group: 65-74 years old) and 348 (aged group: ≥75 years old). The aged individuals had a significant increased risk of OHCA after exposure to minimum temperature <0℃ (odds ratio [OR]: 1.528, 95% confidence interval [CI] 1.009-2.315, P=0.045). Cold ambient temperature was an especially significant increased risk for OHCA occurrence for males (OR: 1.997, 95% CI 1.036-3.773, P=0.039) and during winter (OR: 2.391, 95% CI 1.312-4.360, P=0.004) in the aged group.

CONCLUSIONS

Cold ambient temperature significantly affected aged individuals (≥75 years old) experiencing an OHCA caused by cardiovascular events in indoor environments.

A Pervasive Healthcare System for COPD Patients

Chronic obstructive pulmonary disease (COPD) is one of the most severe public health problems worldwide. Pervasive computing technology creates a new opportunity to redesign the traditional pattern of medical system. While many pervasive healthcare systems are currently found in the literature, there is little published research on the effectiveness of these paradigms in the medical context. This paper designs and validates a rule-based ontology framework for COPD patients. Unlike conventional systems, this work presents a new vision of telemedicine and remote care solutions that will promote individual self-management and autonomy for COPD patients through an advanced decision-making technique. Rules accuracy estimates were 89% for monitoring vital signs, and environmental factors, and 87% for nutrition facts, and physical activities.

Meteorological variables and the risk of fractures: A systematic review and meta-analysis

PURPOSE

The association between meteorological variables and risk of fractures has attracted increasing attentions but remain controversial. Therefore, our main aim is to clarify the association, and also to identify possible susceptible groups.

METHODS

Relevant literature was obtained through standard MeSH literature searching seven electronic databases. Because some studies expressed the association as the rate of incidence (IRR) of fractures associated with each 1 °C rise in temperature and 1% increase in relative humidity (RH), some expressed as IRR of fractures for the day with specific climatic variable versus control days, and also the association was expressed as correlations coefficients (COR) in some studies, separated meta-analyses were undertaken, with one based on IRR and another based on COR.

RESULTS

A total of 24 studies were included. Results showed that each 1 °C increase was significantly associated with a 3.0% decrease in fracture risk (IRR = 0.970, 95%CI: 0.952-0.988). The day with freezing rain and snow were associated with increased risk for both the lower extremity fracture (freezing rain: IRR = 1.174, 95%CI: 1.022-1.348; snow: IRR = 1.245, 95%CI: 1.050-1.477) and the upper extremity fracture (freezing rain: IRR = 1.376, 95%CI: 1.192-1.588; snow: IRR = 1.548, 95%CI: 1.361-1.761). No significant association was detected between RH, dew, frost, fog, storm and high wind, and fracture. The COR meta-analysis showed that mean temperature (moderately), maximum temperature (moderately), rainfall (weakly) and sunlight duration (weakly) were correlated with fracture occurrence.

CONCLUSION

The incidence of fractures was increased in lower temperature, the day with freezing rain, and snow. Other meteorological factors may have some effects on the incidence of fracture. The association maybe stronger for males, lower extremity fracture, and people living in Asia, subtropical zone, low-latitude, and northern hemisphere. Further studies are needed.

The effect of the Winter Fuel Payment on household temperature and health: a regression discontinuity design study

Background

The Winter Fuel Payment (WFP) is a non-NHS population-level policy intervention that aims to reduce cold exposure and enhance the health and well-being of older adults. Labelling this cash transfer as ‘winter fuel’ has been shown to lead to increased household energy expenditure, but it is not known if this expenditure produces warmer homes or health benefits.

Objectives

First, the association between indoor temperature and health was established to identify the outcome measures most likely to be affected by the WFP. Then, whether or not receiving the WFP is associated with raised household temperature levels and/or improved health was assessed.

Design

Random and fixed effects regression models were used to estimate the link between ambient indoor temperature and health. A regression discontinuity (RD) design analysis exploiting the sharp eligibility criteria for the WFP was employed to estimate the potential impact of the payment.

Setting

The sample was drawn from the English Longitudinal Study of Ageing (ELSA), an observational study of community-dwelling individuals aged ≥ 50 years in England.

Participants

Analyses examining the association between household temperature and health had a maximum sample of 12,210 adults aged 50–90 years. The RD analyses drew on a maximum of 5902 observations.

Intervention

The WFP provides households with a member who is aged > 60 years (up to 2010, from which point the minimum age increased) in the qualifying week with a lump sum annual payment, typically in November or December.

Main outcome measures

Differences in indoor temperature were examined, and, following an extensive literature review of relevant participant-reported health indicators and objectively recorded biomarkers likely to be affected by indoor temperature, a series of key measures were selected: blood pressure, inflammation, lung function, the presence of chest infections, subjective health and depressive symptom ratings.

Data sources

The first six waves of the ELSA were drawn from, accessible through the UK Data Service (SN:5050 English Longitudinal Study of Ageing: Waves 0–7, 1998–2015).

Results

Results from both random and fixed-effects multilevel regression models showed that low levels of indoor temperature were associated with raised systolic and diastolic blood pressure levels and raised fibrinogen levels. However, across the RD models, no evidence was found that the WFP was consistently associated with differences in either household temperature or the health of qualifying (vs. non-qualifying) households.

Limitations

The presence of small effects cannot be ruled out, not detectable because of the sample size in the current study.

Conclusions

This study capitalised on the sharp assignment rules regarding WFP eligibility to estimate the potential effect of the WFP on household temperature and health in a national sample of English adults. The RD design employed did not identify evidence linking the WFP to warmer homes or potential health and well-being effects.

Future work

Further research should utilise larger samples of participants close to the WFP eligibility cut-off point examined during particularly cold weather in order to identify whether or not the WFP is linked to health benefits not detected in the current study, which may have implications for population health and the evaluation of the effectiveness of the WFP.

Funding

The National Institute for Health Research Public Health Research programme.

What is cold-related mortality? A multi-disciplinary perspective to inform climate change impact assessments

BACKGROUND

There is a growing discussion regarding the mortality burdens of hot and cold weather and how the balance between these may alter as a result of climate change. Net effects of climate change are often presented, and in some settings these may suggest that reductions in cold-related mortality will outweigh increases in heat-related mortality. However, key to these discussions is that the magnitude of temperature-related mortality is wholly sensitive to the placement of the temperature threshold above or below which effects are modelled. For cold exposure especially, where threshold effects are often ill-defined, choices in threshold placement have varied widely between published studies, even within the same location. Despite this, there is little discussion around appropriate threshold selection and whether reported associations reflect true causal relationships - i.e. whether all deaths occurring below a given temperature threshold can be regarded as cold-related and are therefore likely to decrease as climate warms.

OBJECTIVES

Our objectives are to initiate a discussion around the importance of threshold placement and examine evidence for causality across the full range of temperatures used to quantify cold-related mortality. We examine whether understanding causal mechanisms can inform threshold selection, the interpretation of current and future cold-related health burdens and their use in policy formation.

METHODS

Using Greater London data as an example, we first illustrate the sensitivity of cold related mortality to threshold selection. Using the Bradford Hill criteria as a framework, we then integrate knowledge and evidence from multiple disciplines and areas- including animal and human physiology, epidemiology, biomarker studies and population level studies. This allows for discussion of several possible direct and indirect causal mechanisms operating across the range of 'cold' temperatures and lag periods used in health impact studies, and whether this in turn can inform appropriate threshold placement.

RESULTS

Evidence from a range of disciplines appears to support a causal relationship for cold across a range of temperatures and lag periods, although there is more consistent evidence for a causal effect at more extreme temperatures. It is plausible that 'direct' mechanisms for cold mortality are likely to occur at lower temperatures and 'indirect' mechanisms (e.g. via increased spread of infection) may occur at milder temperatures.

CONCLUSIONS

Separating the effects of 'extreme' and 'moderate' cold (e.g. temperatures between approximately 8-9 °C and 18 °C in the UK) could help the interpretation of studies quoting attributable mortality burdens. However there remains the general dilemma of whether it is better to use a lower cold threshold below which we are more certain of a causal relationship, but at the risk of under-estimating deaths attributable to cold.

Meteorological factors to fall: a systematic review

There existed systematic review on studies investigating the association between hip fractures and external risk factors including meteorological factors. Albeit the fact that most serious common fall injury is a hip fracture, it cannot account for all injuries forms of fall. There was a lack of systematic review covering all fall-related injury or deaths to thoroughly summarise meteorological aspects of fall. This study aimed to systematically review epidemiological studies of fall and fall-related circumstances without restriction to hip fracture. A systematic search in three databases, namely PubMed, CINAHL Plus and EMBASE, was performed. Searches in two Chinese databases named the Wanfang Med Online and the China Journal Net were done in addition. A total of 29 studies were identified. The study site, fall cases identification, meteorological factors and findings of all the selected studies were being extracted. The quality of the studies was critically appraised. We identified some of the environmental risk factors to fall among those studies. Ranging from the lower ambient temperature, the presence of snow cover, seasonal factors, and time of the day to location of fall, these factors have different levels of impact related to higher incidence or mortality of fall. To conclude, a better understanding of injury mechanisms is a prerequisite for preventive interventions.

The health benefits of a targeted cash transfer: The UK Winter Fuel Payment

Each year, the UK records 25,000 or more excess winter deaths, primarily among the elderly. A key policy response is the "Winter Fuel Payment" (WFP), a labelled but unconditional cash transfer to households with a member above the female state pension age. The WFP has been shown to raise fuel spending among eligible households. We examine the causal effect of the WFP on health outcomes, including self-reports of chest infection, measured hypertension, and biomarkers of infection and inflammation. We find a robust, 6 percentage point reduction in the incidence of high levels of serum fibrinogen. Reductions in other disease markers point to health benefits, but the estimated effects are less robust.

Career perspective: Kenneth J. Collins

A career interest in thermoregulation research has included wide contrasts in the subjects of enquiry, extending from heat stroke to hypothermia, special investigations in many different purpose-built climatic chambers, laboratory-based biomedical studies together with hospital practice, and field work in tropical climates to physiological surveys on urban populations in temperate environments. The scientific process and need to focus on careful planning of experiments, using the most appropriate methods, selecting the right controls and eventually applying correct statistical analysis do not always follow a smooth transition, as illustrated in this account. The result of endeavour to resolve a human environmental problem, however, is greatly satisfying, and sometimes becomes a unique experience when the solution reveals new fundamental facts.

Is the association between hip fractures and seasonality modified by influenza vaccination? An ecological study

Osteoporotic hip fractures in 4344 patients were more common during winter. Lower temperatures were associated with higher rates of fracture only in those not vaccinated for influenza. Influenza outbreaks increased the risk of hip fractures. Further studies are needed to assess whether influenza vaccination can prevent hip fractures.

INTRODUCTION

Winter seasonality of osteoporotic hip fracture incidence has been demonstrated, yet the explanation for the association is lacking. We hypothesize that the seasonality of osteoporotic hip fracture can be explained by an association between hip fractures and seasonal influenza outbreaks.

METHODS

This retrospective cohort study included all patients admitted to Soroka University Medical Center with a diagnosis of osteoporotic hip fracture (ICD-9 code 820) between the years 2001 and 2013. Patients with malignancies, trauma, and age under 50 were excluded. In a time series analysis, we examined the association between hip fracture incidence and seasonality adjusted for meteorological factors, and population rates of influenza infection and vaccination using Poisson models.

RESULTS

Four thousand three hundred forty-four patients with a hip fracture were included (69% females, mean age 78). Daily fracture rates were significantly higher in winter (1.1 fractures/day) compared to summer, fall, and spring (0.79, 0.90, and 0.91; p < 0.001). In analysis adjusted for seasons and spline function of time, temperatures were associated with hip fractures risk only in those not vaccinated for influenza (n = 2939, for every decrease of 5 °C, RR 1.08, CI 1.02-1.16; p < 0.05). In subgroup analysis during the years with weekly data on national influenza rates (2010-2013), the risk for hip fracture, adjusted for seasons and temperature, was 1.26 2 weeks following a week with high infection burden (CI 1.05;1.51 p = 0.01), while the temperature was not significantly associated with the fracture risk.

CONCLUSIONS

Under dry and warm desert climate, winter hip fracture incidence increase might be associated with influenza infection, and this effect can be negated by influenza vaccination.

Lower Physical Performance in Colder Seasons and Colder Houses: Evidence from a Field Study on Older People Living in the Community

The aim of this paper was to explore the effect of seasonal temperature differences and cold indoor environment in winter on the physical performance of older people living in the community based on a field study. We recruited 162 home-dwelling older people from a rehabilitation facility in the Osaka prefecture, Japan; physical performance data were available from 98/162 (60.5%). At the same time, for some participants, a questionnaire survey and a measurement of the indoor temperature of individual houses were conducted. The analysis showed that there were seasonal trends in the physical performance of older people and that physical performance was worse in the winter compared with the autumn. Furthermore, people living in colder houses had worse physical performance. The findings indicate that keeping the house warm in the winter can help to maintain physical performance.

Evidence of viscerally-mediated cold-defence thermoeffector responses in man

KEY POINTS

Visceral thermoreceptors that modify thermoregulatory responses are widely accepted in animal but not human thermoregulation models. Recently, we have provided evidence of viscerally-mediated sweating alterations in humans during exercise brought about by warm and cool fluid ingestion. In the present study, we characterize the modification of shivering and whole-body thermal sensation during cold stress following the administration of a graded thermal stimuli delivered to the stomach via fluid ingestion at 52, 37, 22 and 7°C. Despite no differences in core and skin temperature, fluid ingestion at 52°C rapidly decreased shivering and sensations of cold compared to 37°C, whereas fluid ingestion at 22 and 7°C led to equivalent increases in these responses. Warm and cold fluid ingestion independently modifies cold defence thermoeffector responses, supporting the presence of visceral thermoreceptors in humans. However, the cold-defence thermoeffector response patterns differed from previously identified hot-defence thermoeffectors.

ABSTRACT

Sudomotor activity is modified by both warm and cold fluid ingestion during heat stress, independently of differences in core and skin temperatures, suggesting independent viscerally-mediated modification of thermoeffectors. The present study aimed to determine whether visceral thermoreceptors modify shivering responses to cold stress. Ten males (mean ± SD: age 27 ± 5 years; height 1.73 ± 0.06 m, weight 78.4 ± 10.7 kg) underwent whole-body cooling via a water perfusion suit at 5°C, on four occasions, to induce a steady-state shivering response, at which point two aliquots of 1.5 ml kg^-1 (SML) and 3.0 ml kg^-1 (LRG), separated by 20 min, of water at 7, 22, 37 or 52°C were ingested. Rectal, mean skin and mean body temperature (T_b ), electromyographic activity (EMG), metabolic rate (M) and whole-body thermal sensation on a visual analogue scale (WBTS) ranging from 0 mm (very cold) to 200 mm (very hot) were all measured throughout. T_b was not different between all fluid temperatures following SML fluid ingestion (7°C: 35.7 ± 0.5°C; 22°C: 35.6 ± 0.5°C; 37°C: 35.5 ± 0.4°C; 52°C: 35.5 ± 0.4°C; P = 0.27) or LRG fluid ingestion (7°C: 35.3 ± 0.6°C; 22°C: 35.3 ± 0.5°C; 37°C: 35.2 ± 0.5°C; 52°C: 35.3 ± 0.5°C; P = 0.99). With SML fluid ingestion, greater metabolic rates and cooler thermal sensations were observed with ingestion at 7°C (M: 179 ± 55 W, WBTS: 29 ± 21 mm) compared to 52°C (M: 164 ± 34 W, WBTS: 51 ± 28 mm; all P < 0.05). With LRG ingestion, compared to shivering and thermal sensations with ingestion at 37°C (M: 215 ± 47 W, EMG: 3.9 ± 2.5% MVC, WBTS: 33 ± 2 mm), values were different (all P < 0.05) following ingestion at 7°C (M: 269 ± 77 W, EMG: 5.5 ± 0.9% MVC, WBTS: 14 ± 12 mm), 22°C (M: 270 ± 86 W, EMG: 5.6 ± 1.0% MVC, WBTS: 18 ± 19 mm) and 52°C (M: 179 ± 34 W, EMG: 3.3 ± 2.1% MVC, WBTS: 53 ± 28 mm). In conclusion, fluid ingestion at 52°C decreased shivering and the sensation of coolness, whereas fluid ingestion at 22 and 7°C increased shivering and sensations of coolness to similar levels, independently of core and skin temperature.

Renal sympathetic nerve, blood flow, and epithelial transport responses to thermal stress

Thermal stress is a profound sympathetic stress in humans; kidney responses involve altered renal sympathetic nerve activity (RSNA), renal blood flow, and renal epithelial transport. During mild cold stress, RSNA spectral power but not total activity is altered, renal blood flow is maintained or decreased, and epithelial transport is altered consistent with a sympathetic stress coupled with central volume loaded state. Hypothermia decreases RSNA, renal blood flow, and epithelial transport. During mild heat stress, RSNA is increased, renal blood flow is decreased, and epithelial transport is increased consistent with a sympathetic stress coupled with a central volume unloaded state. Hyperthermia extends these directional changes, until heat illness results. Because kidney responses are very difficult to study in humans in vivo, this review describes and qualitatively evaluates an in vivo human skin model of sympathetically regulated epithelial tissue compared to that of the nephron. This model utilizes skin responses to thermal stress, involving 1) increased skin sympathetic nerve activity (SSNA), decreased skin blood flow, and suppressed eccrine epithelial transport during cold stress; and 2) increased SSNA, skin blood flow, and eccrine epithelial transport during heat stress. This model appears to mimic aspects of the renal responses. Investigations of skin responses, which parallel certain renal responses, may aid understanding of epithelial-sympathetic nervous system interactions during cold and heat stress.

Techniques for estimating blood pressure variation using video images

It is important to know about a sudden blood pressure change that occurs in everyday life and may pose a danger to human health. However, monitoring the blood pressure variation in daily life is difficult because a bulky and expensive sensor is needed to measure the blood pressure continuously. In this study, a new non-contact method is proposed to estimate the blood pressure variation using video images. In this method, the pulse propagation time difference or instantaneous phase difference is calculated between two pulse waves obtained from different parts of a subject's body captured by a video camera. The forehead, left cheek, and right hand are selected as regions to obtain pulse waves. Both the pulse propagation time difference and instantaneous phase difference were calculated from the video images of 20 healthy subjects performing the Valsalva maneuver. These indices are considered to have a negative correlation with the blood pressure variation because they approximate the pulse transit time obtained from a photoplethysmograph. However, the experimental results showed that the correlation coefficients between the blood pressure and the proposed indices were approximately 0.6 for the pulse wave obtained from the right hand. This result is considered to be due to the difference in the transmission depth into the skin between the green and infrared light used as light sources for the video image and conventional photoplethysmogram, respectively. In addition, the difference in the innervation of the face and hand may be related to the results.

Sympathetic regulation during thermal stress in human aging and disease

Humans control their core temperature within a narrow range via precise adjustments of the autonomic nervous system. In response to changing core and/or skin temperature, several critical thermoregulatory reflex effector responses are initiated and include shivering, sweating, and changes in cutaneous blood flow. Cutaneous vasomotor adjustments, mediated by modulations in sympathetic nerve activity (SNA), aid in the maintenance of thermal homeostasis during cold and heat stress since (1) they serve as the first line of defense of body temperature and are initiated before other thermoregulatory effectors, and (2) they are on the efferent arm of non-thermoregulatory reflex systems, aiding in the maintenance of blood pressure and organ perfusion. This review article highlights the sympathetic responses of humans to thermal stress, with a specific focus on primary aging as well as impairments that occur in both heart disease and type 2 diabetes mellitus. Age- and pathology-related changes in efferent muscle and skin SNA during cold and heat stress, measured directly in humans using microneurography, are discussed.

Fuel poverty as a major determinant of perceived health: the case of France

OBJECTIVES

The number of households in fuel poverty is growing. Individuals increasingly struggle to heat their homes, and therefore, a growing number of individuals are exposed to low temperatures, which can affect their health. This study sought to determine the link between a subjective measure of fuel poverty (self-reported feeling cold) and self-reported health. The impact of other particular individual and environmental features on self-reported health were also analysed.

STUDY DESIGN

Econometric analysis.

METHODS

The study method uses self-reported perception of thermal discomfort (self-reported feeling cold) as a proxy for fuel poverty. The French database of the Healthcare and Insurance survey carried by the Institute for Research and Information on Health Economics (IRDES) was used to estimate a dichotomous probit model.

RESULTS

The estimation allows us to infer a negative impact of fuel poverty on self-reported health. Thus, a person in fuel poverty is 2.36 percentage points more likely to report poor or fair health status than a person who is not in fuel poverty.

CONCLUSION

It may be appropriate to reduce the impacts of fuel poverty to provide support for the most vulnerable categories of individuals with respect to the health impacts of fuel poverty and cold homes, e.g., chronic patients who experience difficulty heating their homes.

Effect of cold indoor environment on physical performance of older women living in the community

BACKGROUND

the effects of cold on older persons' body and mind are not well documented, but with an increased number of older people with decreasing physical performance, these possible effects need to be understood.

OBJECTIVE

to investigate the effect of cold indoor environment on physical performance of older women.

DESIGN

cross-sectional experimental study with two test conditions.

SETTING

movement laboratory in a climate chamber.

SUBJECTS

eighty-eight community-dwelling, cognitively unimpaired older women (mean age 78 years).

METHODS

participants were exposed to moderately cold (15°C) and warm/normal (25°C) temperature in a climate chamber in random order with an interval of 1 week. The assessment protocol included leg extensor power (Nottingham Power Rig), sit-to-stand performance velocity (linear encoder), gait speed, walk-ratio (i.e. step length/cadence on an instrumented walk way), maximal quadriceps and hand grip strength.

RESULTS

physical performance was lower in 15°C room temperature compared with 25°C room temperature for leg extensor power (P < 0.0001), sit-to-stand performance velocity (P < 0.0001), gait speed (P < 0.0001), walk-ratio (P = 0.016) and maximal quadriceps strength (P = 0.015), but not for hand grip strength.

CONCLUSION

in healthy older women a moderately cold indoor environment decreased important physical performance measures necessary for independent living.

Increased systolic blood pressure after mild cold and rewarming: relation to cold-induced thermogenesis and age

AIM

Higher winter mortality in elderly has been associated with augmented systolic blood pressure (SBP) response and with impaired defense of core temperature. Here we investigated whether the augmented SBP upon mild cold exposure remains after a rewarming period, and whether SBP changes are linked to thermoregulation. Therefore, we tested the following hypotheses: cold-induced increase in SBP (1) remains augmented after rewarming in elderly compared to young adults (2) is related to non-shivering thermogenesis (NST) upon mild cold (3) is related to vasoconstriction upon mild cold.

METHODS

Blood pressure, energy expenditure (EE), skin and core temperature, skin perfusion (abdomen, forearm, both sides of hand) and % body fat were measured in 12 young adults (Y) and 12 elderly (E). Supine subjects were exposed to a thermoneutral baseline 0.5 h (T(air) = 30.1°C), 1 h mild cold (T(air) = 20.7°C), 1 h rewarming (T(air) = 34.8°C) and 1 h baseline (T(air) = 30.5°C).

RESULTS

Upon mild cold only the young adults showed significant NST (Y: +2.5 ± 0.6 W m(-2), P < 0.05). No significant age effects in vasoconstriction were observed. After rewarming per cent change in SBP (%ΔSBP) remained significantly increased in both age groups and was augmented in elderly (Y: +5.0% ± 1.2% vs. E: +14.7% ± 3.1%, P < 0.05). Regression analysis revealed that %ΔSBP significantly related to ΔEE upon mild cold (P < 0.01, r(2) = 0.35) and in elderly also to %body fat (P < 0.02, r(2) = 0.57).

CONCLUSION

Individual changes in SBP after rewarming correlate negatively to NST. Elderly did not show NST, which explains the greater SBP increase in this group. In elderly a relatively large %body fat protected against the adverse effects of mild cold.

Aging affects the cardiovascular responses to cold stress in humans

Cardiovascular-related mortality peaks during cold winter months, particularly in older adults. Acute physiological responses, such as increases in blood pressure, in response to cold exposure may contribute to these associations. To determine whether the blood pressure-raising effect (pressor response) of non-internal body temperature-reducing cold stress is greater with age, we measured physiological responses to 20 min of superficial skin cooling, via water-perfused suit, in 12 younger [25 +/- 1 (SE) yr old] and 12 older (65 +/- 2 yr old) adults. We found that superficial skin cooling elicited an increase in blood pressure from resting levels (pressor response; P < 0.05) in younger and older adults. However, the magnitude of this pressor response (systolic and mean blood pressure) was more than twofold higher in older adults (P < 0.05 vs. younger adults). The magnitude of the pressor response was similar at peripheral (brachial) and central (estimated in the aorta) measurement sites. Regression analysis revealed that aortic pulse wave velocity, a measure of central arterial stiffness obtained before cooling, was the best predictor of the increased pressor response to superficial skin cooling in older adults, explaining approximately 63% of its variability. These results indicate that there is a greater pressor response to non-internal body temperature-reducing cold stress with age in humans that may be mediated by increased levels of central arterial stiffness.

Cold-related cardiac mortality in King County, Washington, USA 1980–2001

BACKGROUND

Studies have shown that cardiac deaths increase during the winter months and that death rates can be tightly predicted from temperature rather than other atmospheric phenomena such as barometric pressure, humidity, or pollution.

AIM

The object of this study is to examine the possible relationship between temperature and cardiac death rates in King County, Washington, USA and suggest possible public health measures that can decrease the number of cardiac deaths associated with cold exposure.

SUBJECTS AND METHODS

State death records show that 62,125 total out-of-hospital cardiac-related deaths among persons 55 years and older occurred in King County between 1980 and 2001. We use Poisson regression to examine the association between same-day daily average temperature and death rate after adjusting for seasonal effects.

RESULTS

We identified a significant negative association between daily average temperature and cardiac mortality among persons over 55 years of age. A 5 degrees C increase in temperature was associated with a decrease in death rate by a factor of 0.971 (95% CI: 0.961, 0.982).

CONCLUSION

Cold temperatures may be an important triggering factor in bringing on the onset of life-threatening cardiac events, even in regions with relatively mild winters. Public health efforts stressing cold exposure while out of doors may play a prominent role in encouraging a reduction in cold stress, especially among seniors and those already at higher risk of cardiac death.

Preventing tomorrow's sudden cardiac death in epilepsy today: what should physicians know about this?

Approximately 1% of the population has epilepsy, the most common neurological disorder. Moreover, people with epilepsy are more likely to die prematurely than those without epilepsy, and the most common epilepsy-related category of death is sudden unexpected death in epilepsy (SUDEP). Information concerning risk factors for SUDEP is conflicting, but potential risk factors include: age, early onset of epilepsy, duration of epilepsy, uncontrolled seizures, seizure frequency, number of antiepileptic drugs and winter temperatures. Additionally, the cause of SUDEP is still unknown; however, the most commonly suggested mechanisms are cardiac abnormalities during and between seizures. This review discusses the epidemiology, risk factors, etiology, and preventative measures in the management of SUDEP.

Seasonal Variations in Blood Pressure

The influence of temperature changes on risk factors like hypertension is often disregarded despite extensive literature on the phenomenon. Numerous surveys and studies have documented the correlation between temperature and blood pressure in various countries among adults, the elderly, and children. Twenty-four-hour blood pressure studies also generally show higher blood pressure in the winter. The suggested etiology is that cold increases sympathetic tone, evidenced by elevated blood pressure and plasma and urinary noradrenaline concentrations. The lower blood pressure in warm temperatures is attributed to cutaneous vasodilatation and loss of water and salt from sweating. Taking seasonal variations in blood pressure into account will increase the meaningful information collected in population surveys and mass screenings. It will also result in more personalized management of antihypertensive medications tailored to the individual.

A deadly harvest: the effects of cold on older people in the UK

Excess winter mortality of some thousands of deaths of older people has occurred in the UK for the past 150 years and shows only moderate abatement. Government policies in both health and social care have had little apparent effect, other than a slow decline in seasonality due largely to secular trends. There are a number of apparent misconceptions, commonly held in the public mind and subsumed in public policy, which need to be corrected in order to reduce the toll of winter cold on older people. The evidence shows that winter deaths are to a large extent avoidable. They are not due to hypothermia as is widely believed, may not be necessarily reduced by climate change in the foreseeable future and may only be partially reduced by improving indoor warmth alone. The key is an integrated policy which reduces all risks equally. Community nursing is well placed to play a pivotal role in such policies.

Housing related difficulties, housing tenure and variations in health status: evidence from older people in Wales

This study aimed to examine housing-related difficulties, the relationship with housing tenure and the subsequent influences on health status in a population sample of older people in Wales. Comparisons with health status normative data were undertaken to determine any geographical differences. A random sample of respondents were interviewed in their own homes (N=423). Data included demographic information, self-reported health status, housing problems, tenure and factors relating to energy efficiency. Univariate analysis found that owner occupiers reported the least housing difficulties and the best health status. Those in public rented properties experienced the most difficulties and the poorest health. The health status of the sample was generally poorer than the norms. Multivariate analysis found that housing difficulties, being cold with current heating and hours spent at home predicted poorer health status. This suggests that characteristics of the home environment may help to explain the differences between tenure and health. Considerable financial outlay may be required to meet policy initiatives that support older people remaining independent, autonomous and able to 'age in place'.

The effects of weather and seasonality on hip fracture incidence in older adults

This study examined the effect of weather and seasonality on hipfracture incidence in older adults residing in New York City. A total off 66,346 patients aged > or = 65 years who sustained a fracture of the femoralneck or intertrochanteric region from 1985 to 1996 comprised the study population. Hip fractures were more likely to occur in the winter than in any of the other seasons (P<.001). Factors significantly correlated with hip fractureincluded minimum daily temperature (r=.167, P<.001), daily wind speed (r=.166, P<.001), maximum daily temperature (r=.155, P<.001), minutes of sunshine (r=.067, P<.01), and average relative humidity (r=.033, P=.03). A greater number of hip fractures occurred in colder months, withambient temperature rather than any adverse circumstances related to rainor snowfall associated most closely to injury. As most fractures occurredindoors, precipitation is less likely to play a part in hip fracture occurrence in this population.

Winter North Atlantic Oscillation, temperature and ischaemic heart disease mortality in three English counties

As cold weather is an ischaemic heart disease (IHD) risk factor, year-to-year variations of the level of IHD mortality may be partly determined by inter-annual variations in winter climate. This paper investigates whether there is any association between the level of IHD mortality for three English counties and the winter North Atlantic Oscillation (NAO), which exerts a fundamental control on the nature of the winter climate over Western Europe. Correlation and regression analysis was used to explore the nature of the association between IHD mortality and a climate index (CI) that represents the interaction between the NAO and temperature across England for the winters 1974-1975 to 1989-1999. Statistically significant inverse associations between the CI and the level of IHD mortality were found. Generally, high levels of winter IHD mortality are associated with a negative CI, which represents winters with a strong negative phase of the NAO and anomalously low temperatures across England. Moreover, the nature of the CI in the early stages of winter appears to exert a fundamental control on the general level of winter IHD mortality. Because winter climate is able to explain a good proportion of the inter-annual variability of winter mortality, long-lead forecasting of winter IHD mortality appears to be a possibility. The integration of climate-based health forecasts into decision support tools for advanced general winter emergency service and capacity planning could form the basis of an effective adaptive strategy for coping with the health effects of harsh winters.

Socio-economic deprivation and excess winter mortality and emergency hospital admissions in the South Yorkshire Coalfields Health Action Zone, UK

The aims of this study were to describe the pattern of excess winter mortality and emergency hospital admissions in the South Yorkshire Coalfields Health Action Zone, and to examine the relationship between excess winter mortality and emergency hospital admissions and socio-economic deprivation at the enumeration district level. We analysed monthly deaths from 1981 to 1999 and monthly emergency hospital admissions from 1990 to 1999 for cardiovascular disease, respiratory disease and all other causes of death for people aged 45 years and above. We used the enumeration district level Townsend socio-economic deprivation score to categorize enumeration districts by quintile. Excess winter mortality ratios (observed/expected) for females and males, respectively, were 1.70 and 1.58 for respiratory disease, 1.25 and 1.20 for cardiovascular disease, and 1.09 and 1.07 for all other causes of death. The excess winter hospital admission ratio for respiratory disease was 1.80 for females and 1.58 for males. No excess was evident for the other two groups of conditions. We found no significant increase in excess winter mortality ratios with increasing socio-economic deprivation. There was also no significant increase in the excess winter respiratory admission ratio with increasing deprivation. With regard to age, we found P<0.0001 and for all other diseases P>0.001 and also in the excess winter hospital admission ratio for respiratory disease P<0.0001 With regard to sex, the excess ratios were lower in men than in women for both respiratory mortality P<0.05 and respiratory hospital admissions P<0.0001 We also observed that excess winter mortality ratios decreased significantly over the 18-year period for cardiovascular disease P<0.05 and for all other diseases P<0.05. Our results suggest that measures to reduce excess winter mortality should be implemented on a population-wide basis and not limited to socio-economically deprived areas. There may also be a case for tailoring interventions to specifically meet the needs of older people.

Physiological and Subjective Responses in the Elderly When Using Floor Heating and Air Conditioning Systems

The purpose of this study was to investigate the effects of a floor heating and air conditioning system on thermal responses of the elderly. Eight elderly men and eight university students sat for 90 minutes in a chair under the following 3 conditions: air conditioning system (A), floor heating system (F) and no heating system (C). The air temperature of sitting head height for condition A was 25 degrees C, and the maximum difference in vertical air temperature was 4 degrees C. The air and floor temperature for condition F were 21 and 29 degrees C, respectively. The air temperature for condition C was 15 degrees C. There were no significant differences in rectal temperature and mean skin temperature between condition A and F. Systolic blood pressure of the elderly men in condition C significantly increased compared to those in condition A and F. No significant differences in systolic blood pressure between condition A and F were found. The percentage of subjects who felt comfortable under condition F was higher than that of those under condition A in both age groups, though the differences between condition F and A was not significant. Relationships between thermal comfort and peripheral (e.g., instep, calf, hand) skin temperature, and the relationship between thermal comfort and leg thermal sensation were significant for both age groups. However, the back and chest skin temperature and back thermal sensation for the elderly, in contrast to that for the young, was not significantly related to thermal comfort. These findings suggested that thermal responses and physiological strain using the floor heating system did not significantly differ from that using the air conditioning system, regardless of the subject age and despite the fact that the air temperature with the floor heating system was lower. An increase in BP for elderly was observed under the condition in which the air temperature was 15 degrees C, and it was suggested that it was necessary for the elderly people to heat the room somehow in winter. Moreover, it is particularly important for elderly people to avoid a decrease in peripheral skin temperature, and maintain awareness of the warmth of peripheral areas, such as the leg, in order to ensure thermal comfort.

Seasonal hypertension: a clue to explain the high prevalence of unrecognized hypertension in the elderly? Gruppo Italiano di Farmacovigilanza nell'Anziano (GIFA)

BACKGROUND AND AIMS

Blood pressure is known to be influenced by the season, particularly in the elderly. The association between cold weather and unrecognized hypertension has not been previously studied. The present study aimed at assessing whether recognition of hypertension in the elderly follows a seasonal pattern.

METHODS

All patients over 64 with either first-listed or secondary diagnosis of hypertension at discharge (N = 4487) out of 24585 consecutively admitted to 69 wards of Geriatrics or Internal Medicine during ten bi-monthly observation periods (May-June and September-October) were enrolled. The main outcome of the study was the prevalence of unrecognized hypertension, defined as no mention of hypertension and/or antihypertensive drugs in clinical histories collected on admission, and a first-listed or secondary discharge diagnosis of hypertension.

RESULTS

We found a total of 928 patients with unrecognized hypertension. Being admitted in the September-October period was independently associated with the outcome unrecognized hypertension (OR 1.25, 95% CI 1.08-1.46), as were smoking addiction (OR 1.57, 95% CI 1.23-2.0) and allocation to a medical ward (OR 1.21, 95% CI 1.04-1.41). Negative correlates of the outcome were multiple pathologies (OR 0.85, 95% CI 0.73-0.99), discharge diagnosis of coronary artery disease (OR 0.77, 95% CI 0.64-0.92) or diabetes mellitus (OR 0.81, 95% CI 0.67-0.97).

CONCLUSIONS

Hypertension in the elderly may at least partly follow a seasonal pattern, and this finding may be relevant for screening and therapeutic decisions.

Elevated risk of high blood pressure: climate and the inverse housing law

BACKGROUND

In previous work the authors identified an 'inverse housing law' in Britain such that housing quality tends to be worse in areas of harsh climate than in areas where the climate is more benign. This study investigates whether an individual's risk of hypertension is associated with such a 'mismatch' between the quality of their housing and the climate to which they have been exposed.

METHODS

Cross-sectional observational study based on Britain. Data came from the 5663 Health and Lifestyle Survey (HALS) participants for whom all relevant items were available. A two-stage study design was employed. First, the relationship between exposure to colder climate and housing quality was established. Second, the impact on risk of hypertension was determined for level of exposure to colder climate and housing quality.

RESULTS

Analysis confirmed that amongst survey respondents, those with greater exposure to colder climate are more likely (1.32, 95% CI: 1.18-1.42) to live in poor quality housing than those with lower exposure to colder climate. This combination of higher exposure to colder climate plus residence in worse quality housing raises significantly the risk of diastolic hypertension (1.45, 95% CI: 1.18-1.77) and, more weakly, systolic hypertension (1.25, 95% CI: 1.01-1.53).

CONCLUSIONS

There appears to be an 'inverse housing law' in Britain, whereby longer term residents of relatively cold areas are also more likely to live in worse quality housing and this combination of circumstances is associated with significantly higher risk of diastolic hypertension. The findings provide an example of how long term exposure to an adverse environment, which may stem from material disadvantage, can damage health.

Effect of age on chronological variation of acute myocardial infarction onset: study in Japan

To evaluate the effect of age on circadian and seasonal variation in the onset of acute myocardial infarction (AMI) in Japan, we studied 725 patients whose onset date and time of the symptom were determined. In the analysis of all AMI patients, the occurrence showed significant circadian variation (P< 0.01); 30% of episodes occurred between 0600 and 1200h which formed a dominant morning peak. In the analysis of separate age-groups, a significant difference in the occurrence among four 6-hour periods of day was observed only in the early-elderly group (65-74 years), in which a significant (P < 0.01) morning peak comprising 33% of episodes was observed between 0600 and 1200 h. The monthly variation of AMI onset in total subjects tended to show two peaks; April and August. The seasonal variation tended to show a trough in autumn when analyzed in all patients, but the variation was significant only in middle-aged group (< 65 years). In conclusion, the incidence of AMI in Japanese population showed dominant morning peak, and tended to show autumn trough. These circadian and seasonal variations were affected by age.