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Shakoor Hajat

Publications and source records attributed to Shakoor Hajat.

14 recordsLinked to original sources
PubMed2006

Declining vulnerability to temperature-related mortality in London over the 20th century.

The degree to which population vulnerability to outdoor temperature is reduced by improvements in infrastructure, technology, and general health has an important bearing on what realistically can be expected with future changes in climate. Using autoregressive Poisson models with adjustment for season, the authors analyzed weekly mortality in London, United Kingdom, during four periods (1900-1910, 1927-1937, 1954-1964, and 1986-1996) to quantify changing vulnerability to seasonal and temperature-related mortality throughout the 20th century. Mortality patterns showed an epidemiologic transition over the century from high childhood mortality to low childhood mortality and towards a predominance of chronic disease mortality in later periods. The ratio of winter deaths to nonwinter deaths was 1.24 (95% confidence interval (CI): 1.16, 1.34) in 1900-1910, 1.54 (95% CI: 1.42, 1.68) in 1927-1937, 1.48 (95% CI: 1.35, 1.64) in 1954-1964, and 1.22 (95% CI: 1.13, 1.31) in 1986-1996. The temperature-mortality gradient for cold deaths diminished progressively: The increase in mortality per 1 degree C drop below 15 degrees C was 2.52% (95% CI: 2.00, 3.03), 2.34% (95% CI: 1.72, 2.96), 1.64% (1.10, 2.19), and 1.17% (95% CI: 0.88, 1.45), respectively, in the four periods. Corresponding population attributable fractions were 12.5%, 11.2%, 8.7%, and 5.4%. Heat deaths also diminished over the century. There was a progressive reduction in temperature-related deaths over the 20th century, despite an aging population. This trend is likely to reflect improvements in social, environmental, behavioral, and health-care factors and has implications for the assessment of future burdens of heat and cold mortality.

Adolescent↗
PubMed2006

The association of respiratory syncytial virus infection and influenza with emergency admissions for respiratory disease in London: an analysis of routine surveillance data.

BACKGROUND: The importance of respiratory syncytial virus (RSV) infection in adults is not well known, because laboratory testing for RSV infection is not routine. Both RSV infection and influenza are seasonally related, and it is difficult to disentangle one from the other and to disentangle infection from the season and the cold. METHODS: Emergency hospitalizations for respiratory disease from April 1994 to March 2001 were analyzed in relation to surveillance data on RSV infection and influenza, using Poisson regression models adapted for time series and adjusted for season, outdoor temperature, and other covariates. Age-specific admission rates attributable to the viruses were also estimated. RESULTS: Most of the crude relationships of emergency admissions of patients with RSV infection were confounded by season and, to a lesser extent, by cold temperatures. After adjustment for all covariates, including influenza, a 10th-90th percentile increase in RSV counts (defined as the daily number of laboratory reports of RSV) was associated with a rate ratio of 1.36 (95% CI, 1.27-1.45) for emergency admissions for respiratory disease in infants. The rate of hospitalization attributable to RSV infection in children aged <1 year was 5 per 1000 infants per year. The association in people > or =65 years old was much smaller (rate ratio, 1.09; 95% CI, 1.04-1.14; attributable rate of hospitalization , 0.7 per 1000 population); but unlike the association in infants, this association became smaller as the lag (interval) between infection and hospital admission became shorter. Admission rates attributable to influenza were highest in the > or =65-year age group (1.1 per 1000 population), but it was very small at younger ages. CONCLUSIONS: RSV infection appears to be an important determinant of hospitalization in infants in this data set but appears less certain for older persons and requires further investigation.

Adolescent↗
PubMed2006

Contrasting patterns of hospital admissions and mortality during heat waves: are deaths from circulatory disease a real excess or an artifact?

In old subjects exposed to extreme high temperature during a heat wave, studies have consistently reported an excess of death from cardio- or cerebro-vascular disease. By contrast, dehydration, heat stroke, acute renal insufficiency, and respiratory disease were the main causes of hospital admission in the two studies carried out in elderly during short spells of hot weather. The excess of circulatory disease reported by mortality studies, but not by morbidity studies, could be explained by the hypothesis that deaths from circulatory disease occur rapidly in isolated people before they reach a hospital. Since the contrasting patterns of hospital admission and mortality during heat waves could also be due to chance (random variation over time and space in the spectrum of diseases induced by extreme heat), and bias (poor quality of diagnosis on death certificate and other artifacts), it should be confirmed by a concurrent study of mortality and morbidity. Many heat-related diseases may be preventable with adequate warning and an appropriate response to heat emergencies, but preventive efforts are complicated by the short time interval that may elapse between high temperatures and death. Therefore, prevention programs must be based around rapid identification of high-risk conditions and persons. The effectiveness of the intervention measures must be formally evaluated. If cardio- and cerebro-vascular diseases are rapidly fatal health outcomes with a short time interval between exposure to high temperature and death, deaths from circulatory disease might be an useful indicator in evaluating the effectiveness of a heat watch/warning system.

Artifacts↗
PubMed2006

Impact of high temperatures on mortality: is there an added heat wave effect?

BACKGROUND: Mortality during sustained periods of hot weather is generally regarded as being in excess of what would be predicted from smooth temperature-mortality gradients estimated using standard time-series regression models. However, the evidence for an effect of continuous days of exceptional heat ("heat wave effect") is indirect. In addition, because some interventions may be triggered only during forecasted heat waves, it would be helpful to know what fraction of all heat-related deaths falls during these specific periods and what fraction occurs throughout the remainder of the summer. METHODS: Extended time-series data sets of daily mortality counts in 3 major European cities (London, 28 years of data; Budapest, 31 years; Milan, 18 years) were examined in relation to hot weather using a generalized estimating equations approach. We modeled temperature and specific heat wave terms using a variety of specifications. RESULTS: With a linear effect of same-day temperature above an identified threshold, an additional "heat wave" effect of 5.5% was observed in London (95% confidence interval = 2.2 to 8.9), 9.3% in Budapest (5.8 to 13.0), and 15.2% in Milan (5.7 to 22.5). Heat wave effects were reduced slightly when we relaxed the linear assumption and these effects were reduced substantially when temperature was modeled as an average value of lags 0 to 2 days. In London, fewer than half of all heat-related deaths could be attributed to identified heat wave periods. In Milan and Budapest, the fraction was less than one fifth. CONCLUSIONS: Heat wave effects were apparent in simple time-series models but were reduced in multilag nonlinear models and small when compared with the overall summertime mortality burden of heat. Reduction of the overall heat burden requires preventive measures in addition to those that target warnings and responses uniquely to heat waves.

Epidemiologic Methods↗
PubMed2005

Impact of control for air pollution and respiratory epidemics on the estimated associations of temperature and daily mortality.

We assessed the influence of control for air pollution and respiratory epidemics on associations between apparent temperature (AT) and daily mortality in Mexico City and Monterrey. Poisson regressions were fit to mortality among all ages, children (ages 0-14 years) and the elderly (ages >or=65 years). Predictors included mean daily AT, season, day of week and public holidays for the base model. Respiratory epidemics and air pollution (particulate matter <10 microm in aerodynamic diameter and O3) were added singly and then jointly for a fully adjusted model. Percent changes in mortality were calculated for days of relatively extreme temperatures [cold (10-11 degrees C) for both cities and heat (35-36 degrees C) for Monterrey], compared to days at the overall mean temperature in each city (15 degrees C in Mexico City, 25 degrees C in Monterrey). In Mexico City, total mortality increased 12.4% [95% confidence interval (CI) 10.5%, 14.5%] on cold days (fully adjusted). Among children, the adjusted association was similar [10.9% (95% CI: 5.4%, 16.7%)], but without control for pollution and epidemics, was nearly twice as large [19.7% (95% CI: 13.9%, 25.9)]. In Monterrey, the fully adjusted heat effect for all deaths was 18.7% (95% CI: 11.7%, 26.1%), a third lower than the unadjusted estimate; the heat effect was lower among children [5.5% (95% CI: -10.1%, 23.8%)]. Cold had a similar effect on all-age mortality as in Mexico City [11.7% (95% CI: 3.7%, 20.3%)]. Responses of the elderly differed little from all-ages responses in both cities. Associations between weather and health persisted even with control for air pollution and respiratory epidemics in two Mexican cities, but risk assessments and climate change adaptation programs are best informed by analyses that account for these potential confounders.

Adolescent↗
PubMed2005

Mortality displacement of heat-related deaths: a comparison of Delhi, São Paulo, and London.

BACKGROUND: Mortality increases with hot weather, although the extent to which lives are shortened is rarely quantified. We compare the extent to which short-term mortality displacement can explain heat deaths in Delhi, São Paulo, and London given contrasting demographic and health profiles. METHODS: We examined time-series of daily mortality data in relation to daily ambient temperature using Poisson models and adjusting for season, relative humidity, rainfall, particulate air pollution, day of the week, and public holidays. We used unconstrained distributed lag models to identify the extent to which heat-related excesses were followed by deficits (mortality displacement). RESULTS: For each city, an increase in all-cause mortality was observed with same-day (lag 0) and previous day (lag 1) temperatures greater than a threshold of 20 degrees C. At lag 0, the excess risk was greatest in Delhi and smallest in London. In Delhi, an excess was apparent up to 3 weeks after exposure, after which a deficit was observed that offset just part of the overall excess. In London, the heat excess persisted only 2 days and was followed by deficits, such that the sum of effects was 0 by day 11. The pattern in São Paulo was intermediate between these. The risk summed over the course of 28 days was 2.4% (95% confidence interval = 0.1 to 4.7%) per degree greater than the heat threshold in Delhi, 0.8% (-0.4 to 2.1%) in São Paulo and -1.6% (-3.4 to 0.3%) in London. Excess risks were sustained up to 4 weeks for respiratory deaths in São Paulo and London and for children in Delhi. CONCLUSIONS: Heat-related short-term mortality displacement was high in London but less in Delhi, where infectious and childhood mortality still predominate.

Adolescent↗
PubMed2004

Climate variability and campylobacter infection: an international study.

Campylobacter is among the most important agents of enteritis in developed countries. We have described the potential environmental determinants of the seasonal pattern of infection with campylobacter in Europe, Canada, Australia and New Zealand. Specifically, we investigated the role of climate variability on laboratory-confirmed cases of campylobacter infection from 15 populations. Regression analysis was used to quantify the associations between timing of seasonal peaks in infection in space and time. The short-term association between weekly weather and cases was also investigated using Poisson regression adapted for time series data. All countries in our study showed a distinct seasonality in campylobacter transmission, with many, but not all, populations showing a peak in spring. Countries with milder winters have peaks of infection earlier in the year. The timing of the peak of infection is weakly associated with high temperatures 3 months previously. Weekly variation in campylobacter infection in one region of the UK appeared to be little affected by short-term changes in weather patterns. The geographical variation in the timing of the seasonal peak suggests that climate may be a contributing factor to campylobacter transmission. The main driver of seasonality of campylobacter remains elusive and underscores the need to identify the major serotypes and routes of transmission for this disease.

Australia↗
PubMed2004

Cold weather and GP consultations for respiratory conditions by elderly people in 16 locations in the UK.

BACKGROUND: Cold weather is associated with increases in mortality and demands on hospital services in the UK, particularly by the elderly. Less is known about the relationship with patterns of consultation in primary care. We wished to determine the magnitude and consistency of associations between cold temperature and consultations for respiratory conditions in primary care settings at different sites in the UK. METHODS: Time series analysis of any short-term effects of temperature on daily general practitioner (GP) consultations made by elderly people (65+ years) for lower and upper respiratory tract infections (LRTI, URTI) over a 10-year period, 1992--2001. Practices were situated in 16 urban locations across the UK where a Met Office monitoring station was in operation. RESULTS: An association between low temperatures and an increase in LRTI consultations was observed in all 16 locations studied. The biggest increase was estimated for the Norwich practices for which a 19.0% increase in LRTI consultations (95% CI 13.6, 24.7) was associated with every 1 degrees C drop in mean temperature below 5 degrees C observed 0-20 days before the day of consultation. Slightly weaker relationships were observed in the case of URTI consultations. A north/south gradient, with larger temperature effects in the north, was in evidence for both LRTI and URTI consultations. CONCLUSIONS: An effect that was consistent and generally strongest in populations in the north was observed between cold temperature and respiratory consultations. Better understanding of the mechanisms by which cold weather is associated with increases in consultations for respiratory infections could lead to improved strategies for prevention and reduced burdens for health services.

Aged↗
PubMed2004

Patterns and determinants of alcohol consumption in people aged 75 years and older: results from the MRC trial of assessment and management of older people in the community.

BACKGROUND: Very little work on alcohol consumption patterns in older people has been undertaken. As a result, knowledge about the prevalence and characteristics of regular drinkers and heavy drinkers in this age group remains limited. OBJECTIVE: To determine the socio-economic and health characteristics associated with different levels of alcohol intake in older people. DESIGN: Detailed screening of patients in one arm of a cluster randomised trial. SETTING: 53 UK general practices drawn from the Medical Research Council General Practice Research Framework. SUBJECTS: All patients aged 75 and over on the GP lists (excluding those in nursing homes or other long stay care) were invited to participate in the study. Of the 15358 people who received a detailed assessment in the 'universal' arm, 14962 (97%) of these answered questions on alcohol consumption. Of these, 62% were female and the median age was 80.3 years. METHODS: Associations between reported alcohol intake and various socio-economic and health variables were investigated, first in univariate analyses and then controlling for other variables in logistic regression models. RESULTS: 5% of men and 2.5% of women exceeded the Royal College of Physicians, Psychiatrists and General Practitioners' recommended drinking limits of 21 and 14 units a week respectively; 17% of subjects had never had a drink. Women and the very elderly were less likely to be drinkers. Those that drank were more likely to be people who still had a fairly active and sociable lifestyle, and with a better self-perceived health status compared with non-drinkers. Moderate drinkers were also less likely to be severely cognitively impaired compared with non-drinkers: adjusted odds ratio 0.69 (95% CI 0.57, 0.85); but more likely to report symptoms of anxiety: 1.31 (1.07, 1.61). CONCLUSIONS: Our results suggest that moderate alcohol consumption is associated with relative financial security and good health with the exception of higher levels of anxiety amongst drinkers.

Aged↗
PubMed2003

El Niño and health.

El Niño Southern Oscillation (ENSO) is a climate event that originates in the Pacific Ocean but has wide-ranging consequences for weather around the world, and is especially associated with droughts and floods. The irregular occurrence of El Niño and La Niña events has implications for public health. On a global scale, the human effect of natural disasters increases during El Niño. The effect of ENSO on cholera risk in Bangladesh, and malaria epidemics in parts of South Asia and South America has been well established. The strongest evidence for an association between ENSO and disease is provided by time-series analysis with data series that include more than one event. Evidence for ENSO's effect on other mosquito-borne and rodent-borne diseases is weaker than that for malaria and cholera. Health planners are used to dealing with spatial risk concepts but have little experience with temporal risk management. ENSO and seasonal climate forecasts might offer the opportunity to target scarce resources for epidemic control and disaster preparedness.

Climate↗
PubMed2003

Socioeconomic differentials in the temperature-mortality relationship in São Paulo, Brazil.

BACKGROUND: We investigated the impact of environmental temperature on mortality in São Paulo, Brazil, and examined differences in the temperature-mortality relationship with respect to cause, age group, and socioeconomic position (SEP). METHODS: Generalized additive Poisson regression models adjusted for non-temperature related seasonal factors (including air pollution) were used to analyse daily mortality counts for selected causes from 1991 to 1994. Individuals were classified by the aggregate SEP of their area of residency. These were analysed as potential modifiers of the temperature-mortality relationship. RESULTS: Among the elderly we observed a 2.6% increase in all-cause mortality per degree increase in temperature above 20 degrees C, and a 5.5% increase per degree drop in temperature below 20 degrees C, after adjustment for confounding. Relationships were similar in children, but somewhat weaker in adults. Cold effects were present for deaths due to cardiovascular disease (CVD), respiratory, and other causes, with effects being greatest in the respiratory group. Heat effects were not found for CVD deaths in adults, but otherwise varied little by cause of mortality. There was little evidence for a modification of the mortality effects of cold or heat by SEP. CONCLUSIONS: These findings show that the U-shaped pattern of the temperature-mortality relationship found in cooler northern countries occurs also in a sub-tropical city. In addition, the relative effects of temperature were similar in each socioeconomic grouping.

Adolescent↗
PubMed2002

Mortality, morbidity, and 1-year outcomes of primary elective total hip arthroplasty.

No representative data exist on the risks of adverse outcomes of total hip arthroplasty (THA) in the United Kingdom. A prospective observational study of unselected THA operations was carried out in 5 U.K. regions. Adverse outcomes were assessed from the hospital case notes and general practitioners of 1,100 randomly selected patients and from 7,151 patient-completed questionnaires 3 and 12 months after THA. Three-month mortality was 0.4% to 0.7%. Dislocation and thromboembolic complications were about 3% and 4%. Perioperative fracture, sciatic nerve palsy, aseptic loosening, and revision each had a risk of < or = 1%. At 1 year, 2.6% of patients had undergone another operation on the same hip, 11% reported moderate or severe pain in the operated hip, 23% had severe walking restriction, and 11% were dissatisfied with the operation. Patients and surgeons in the United Kingdom should have access to this information when making a decision about THA.

Arthroplasty, Replacement, Hip↗
PubMed2002

Does waiting for total hip replacement matter? Prospective cohort study.

OBJECTIVES: To assess the impact on the outcome of total hip replacement of the length of timing spent waiting for surgery. METHODS: One hundred and forty-three orthopaedic and general hospitals provided information about aspects of surgical practice for each total hip replacement conducted between September 1996 and October 1997 for publicly and privately funded operations in five English health regions. These data were linked to patient information about hip-related pain and disability status (measured using the Oxford Hip Score) before operation and at 3 and 12 months after. Data were analysed using multiple regression analysis. RESULTS: Questionnaires were completed by surgeons for 10,410 (78%) patients treated during the recruitment period and by 7151 (54%) patients. Twelve months after total hip replacement, the majority of patients experienced substantial improvements in hip-related pain and disability (as measured by the Oxford Hip Score). Those patients who started with a worse Oxford Hip Score before the operation tended to remain worse after the operation. Worse pre-operative score was associated with an increased length of either outpatient or inpatient wait, and this trend remained after the operation. The relationship between waiting time and outcome remained after adjustment for possible confounding variables. A consistently worse score was observed in public compared with private patients at all three time-points. In addition, in both sectors, those patients who were socially disadvantaged had a worse score than more socially advantaged patients both before and after the operation. CONCLUSIONS: Waiting for surgery is associated with worse outcomes 12 months later. Longer-term outcome needs to be considered to see if this association persists.

Activities of Daily Living↗