Development and validation of a new predictive model for breast cancer survival in New Zealand and comparison to the Nottingham prognostic index.

BACKGROUND: The only available predictive models for the outcome of breast cancer patients in New Zealand (NZ) are based on data in other countries. We aimed to develop and validate a predictive model using NZ data for this population, and compare its performance to a widely used overseas model, the Nottingham Prognostic Index (NPI). METHODS: We developed a model to predict 10-year breast cancer-specific survival, using data collected prospectively in the largest population-based regional breast cancer registry in NZ (Auckland, 9182 patients), and assessed its performance in this data set (internal validation) and in an independent NZ population-based series of 2625 patients in Waikato (external validation). The data included all women with primary invasive breast cancer diagnosed from 1 June 2000 to 30 June 2014, with follow up to death or Dec 31, 2014. We used multivariate Cox proportional hazards regression to assess predictors and to calculate predicted 10-year breast cancer mortality, and therefore survival, probability for each patient. We assessed observed survival by the Kaplan Meier method. We assessed discrimination by the C statistic, and calibration by comparing predicted and observed survival rates for patients in 10 groups ordered by predicted 10-year survival. We compared this NZ model with the Nottingham Prognostic Index (NPI) in this validation data set. RESULTS: Discrimination was good: C statistics were 0.84 for internal validity and 0.83 for an independent external validity. For calibration, for both internal and external validity the predicted 10-year survival probabilities in all groups of patients, ordered by predicted survival, were within the 95% confidence intervals (CI) of the observed Kaplan-Meier survival probabilities. The NZ model showed good discrimination even within the prognostic groups defined by the NPI. CONCLUSIONS: These results for the New Zealand model show good internal and external validity, transportability, and potential clinical value of the model, and its clear superiority over the NPI. Further research is needed to assess other potential predictors, to assess the model's performance in specific subgroups of patients, and to compare it to other models, which have been developed in other countries and have not yet been tested in NZ.

An international ecological study of adult height in relation to cancer incidence for 24 anatomical sites.

BACKGROUND: Anthropometric indices associated with childhood growth and height attained in adulthood, have been associated with an increased incidence of certain malignancies. To evaluate the cancer-height relationship, we carried out a study using international data, comparing various cancer rates with average adult height of women and men in different countries. METHODS: An ecological analysis of the relationship between country-specific cancer incidence rates and average adult height was conducted for twenty-four anatomical cancer sites. Age-standardized rates were obtained from GLOBOCAN 2008. Average female (112 countries) and male (65 countries) heights were sourced and compiled primarily from national health surveys. Graphical and weighted regression analysis was conducted, taking into account BMI and controlling for the random effect of global regions. RESULTS: A significant positive association between a country's average adult height and the country's overall cancer rate was observed in both men and women. Site-specific cancer incidence for females was positively associated with height for most cancers: lung, kidney, colorectum, bladder, melanoma, brain and nervous system, breast, non-Hodgkin lymphoma, multiple myeloma, corpus uteri, ovary, and leukemia. A significant negative association was observed with cancer of the cervix uteri. In males, site-specific cancer incidence was positively associated with height for cancers of the brain and nervous system, kidney, colorectum, non-Hodgkin lymphoma, multiple myeloma, prostate, testicular, lip and oral cavity, and melanoma. CONCLUSION: Incidence of cancer was associated with tallness in the majority of anatomical/cancer sites investigated. The underlying biological mechanisms are unclear, but may include nutrition and early-life exposure to hormones, and may differ by anatomical site.

C-reactive protein has a better discriminative power than white cell count in the diagnosis of acute cholecystitis.

BACKGROUND: The diagnosis of acute cholecystitis (AC) is challenging and may result in a delay in surgery, hospital discharge, and increased mortality. To improve its diagnosis, C-reactive protein (CRP) has been proposed as a benchmark. The aim of this study was to evaluate discriminative power of CRP against white cell count (WCC) in AC. METHODS: This was a retrospective cohort study. Over a 5-y period, 1959 patients were identified from the audit of cholecystectomies. The exclusion criteria were coexisting acute surgical conditions, absence of blood tests within 3 d before hospital admission for elective surgery, and private patients. RESULTS: The eligibility criteria were met by 1843 patients. Comparison of the area under receiver operating characteristic (AUC) curve of CRP and WCC in acute on chronic, edematous, necrotic, suppurative, and gangrenous AC showed a better discriminative power of CRP. Both tests performed equally well in patients with pericholecystic abscess and gallbladder perforation. CRP was superior than WCC in mild AC, AUC = 0.93 (95% confidence interval [CI], 0.9-0.95) and 0.79 (95% CI, 0.74-0.84), P < 0.00005, in moderate and severe AC, AUC = 0.99 (95% CI, 0.97-1.0) and 0.92 (95% CI, 0.88-0.97), P = 0.009, and in all forms of AC combined, AUC = 0.94; (95% CI, 0.92-0.97) and 0.83 (95% CI, 0.79-0.87), respectively, P < 0.00005. CONCLUSIONS: CRP has a better discriminative power than WCC in most forms of AC and is a useful diagnostic marker of AC.

Is serum urate causally associated with incident cardiovascular disease?

OBJECTIVE: With studies reporting both positive and negative associations, the influence of serum urate on incident cardiovascular disease (CVD) is uncertain. We sought to determine whether serum urate is causally associated with incident CVD. METHODS: Participants were aged 30-80 years and were screened for CVD risk in primary care between 2006 and 2009. Participants had blood pressure, lipids, age and ethnic group recorded at assessment, with record linkage providing drug dispensing, hospital diagnoses and laboratory test results. Outcomes were derived from hospital diagnoses and mortality records until December 2009. Cox models were used to assess the influence of exposures on outcomes. RESULTS: A total of 78 707 people, free of CVD, were enrolled, and 1328 CVD events occurred during follow-up. Serum urate was recorded before baseline assessment in 43% (34 008/78 707) of participants. After adjustment for confounding factors, a 2 s.d. difference in serum urate (0.45 vs 0.27 mmol/l) was associated with a hazard ratio (HR) of 1.56 (95% CI 1.32, 1.84). This was more than double that of the equivalent distributional change in high-density lipoprotein cholesterol (adjusted HR 1.22) and one-third greater than that for HbA1c (adjusted HR 1.41). CONCLUSION: Serum urate is likely to be causally associated with CVD. This supports public health action to reduce urate levels in populations with significant burdens of the disease.

Home hemodialysis and mortality risk in Australian and New Zealand populations.

BACKGROUND: There is a resurgence of interest in home hemodialysis (HD), especially frequent or extended forms involving unconventionally frequent (>3 times/wk) and/or long (>6 hours) treatments. This resurgence is driven by cost containment and experience suggesting lower mortality risk compared with facility HD and peritoneal dialysis (PD). STUDY DESIGN: We performed an observational cohort study using the Australia and New Zealand Dialysis and Transplant Registry, using marginal structural modeling to adjust for time-varying medical comorbidity as both a source of selection bias and an intermediary variable on the causal pathway to death. SETTING & PARTICIPANTS: All adult patients starting renal replacement therapy in Australia and New Zealand since March 31, 1996, followed up to December 31, 2007. PREDICTOR: The main predictor was dialysis modality (conventional facility HD, conventional home HD, frequent/extended facility HD, frequent/extended home HD, and PD). We adjusted for the confounding effects of patient demographics and comorbid conditions. OUTCOME: Patient mortality. RESULTS: We analyzed 26,016 patients with 856,007 patient-months of follow-up. Relative to conventional facility HD, adjusted mortality HRs were 0.51 (95% CI, 0.44-0.59) for conventional home HD, 1.16 (95% CI, 0.94-1.44) for frequent/extended facility HD, 0.53 (95% CI, 0.41-0.68) for frequent/extended home HD, and 1.10 (95% CI, 1.06-1.16) for PD. The apparent benefit of home HD on mortality risk was less for patients who were nonwhite, non-Asian, and older. LIMITATIONS: Potential for residual confounding from the limited collection of comorbid conditions (no collection of cognitive or motor impairment, depression, left ventricular volume or structure, or blood pressure/fluid volume status) and lack of socioeconomic, medication, and biochemical data in analyses. CONCLUSIONS: Our study supports a survival advantage of home HD without a difference between conventional and frequent/extended modalities. Suitably designed clinical trials of frequent/extended HD are needed to determine the presence and extent of mortality benefit with this modality.

Arthroplasty or internal fixation for displaced femoral neck fractures: which is the optimal alternative for elderly patients? A meta-analysis.

We conducted an up-to-date meta-analysis of 20 eligible randomised controlled trials (RCTs) containing 3,109 patients to compare arthroplasty with internal fixation of displaced femoral neck fractures regarding the effect on clinical outcomes. Computerised databases were searched for RCTs published from January 1979 to May 2008. The results showed that compared to internal fixation arthroplasty led to significantly fewer surgical complications at two and five years postoperatively and reduced the incidence of reoperation at one, two and five years postoperatively (P < 0.001). However, arthroplasty was associated with greater risk of deep wound infection, longer operating time and greater operative blood loss. Arthroplasty substantially increased the risk of reoperation following deep wound infection (P < 0.05). For mortality, there was increased postoperative risk for arthroplasty compared with internal fixation, but there was no statistically significant difference between the two groups at the different follow-up times. For pain at one year postoperatively, the result showed no statistically significant difference.

Bias in survival estimates created by a requirement for consent to enter a clinical breast cancer registry.

BACKGROUND: A requirement for consent for inclusion may bias the results from a clinical registry. This study gives a direct measure of this bias, based on a population-based clinical breast cancer registry where the requirement for consent was removed after further ethical review and data could be re-analysed. METHODS: In Auckland, New Zealand, the population-based clinical breast cancer registry required written patient consent for inclusion from 2000-2012. A subsequent ethical review removed this requirement and allowed an analysis of consented and non-consented patients. Kaplan-Meier survival to 10 years (mean follow-up 5.1 years, maximum 13.9 years), demographic and clinical characteristics were compared. Of 9244 women with invasive cancer, 926 (10.4%) were not consented, and of 1642 women with ductal carcinoma in situ, 245 (14.9%) were not consented. RESULTS: Survival was much higher for consenting patients; invasive cancer, 5 year survival 83.2% (95% confidence limits 82.2-84.1%) for consenting patients, 57.1% (53.0-60.9%) for non-consenting, and 80.8% in all patients. Analyses based only on consenting patients overestimate survival in all patients by around 2% at 2, 5, and 10 years. Non-consented patients were older, more often of Pacific ethnicity, had fewer screen-detected cancers, and more often had metastatic disease; they less frequently had primary surgery or systemic treatments. CONCLUSION: Data from a registry requiring active consent gives an upward bias in survival results, as non-consenting patients have more extensive disease, less treatment, and lower survival. To give unbiased results active consent should be not required in a clinical cancer registry.

Design and validation of a comprehensive fecal incontinence questionnaire.

PURPOSE: Fecal incontinence can have a profound effect on quality of life. Its prevalence remains uncertain because of stigma, lack of consistent definition, and dearth of validated measures. This study was designed to develop a valid clinical and epidemiologic questionnaire, building on current literature and expertise. METHODS: Patients and experts undertook face validity testing. Construct validity, criterion validity, and test-retest reliability was undertaken. Construct validity comprised factor analysis and internal consistency of the quality of life scale. The validity of known groups was tested against 77 control subjects by using regression models. Questionnaire results were compared with a stool diary for criterion validity. Test-retest reliability was calculated from repeated questionnaire completion. RESULTS: The questionnaire achieved good face validity. It was completed by 104 patients. The quality of life scale had four underlying traits (factor analysis) and high internal consistency (overall Cronbach alpha = 0.97). Patients and control subjects answered the questionnaire significantly differently (P < 0.01) in known-groups validity testing. Criterion validity assessment found mean differences close to zero. Median reliability for the whole questionnaire was 0.79 (range, 0.35-1). CONCLUSIONS: This questionnaire compares favorably with other available instruments, although the interpretation of stool consistency requires further research. Its sensitivity to treatment still needs to be investigated.

Agreement between ethnicity recorded in two New Zealand health databases: effects of discordance on cardiovascular outcome measures (PREDICT CVD3).

OBJECTIVES: To assess agreement between ethnicity as recorded by two independent databases in New Zealand, PREDICT and the National Health Index (NHI), and to assess sensitivity of ethnic-specific measures of health outcomes to either ethnicity record. METHOD: Patients assessed using PREDICT form the study cohort. Ethnicity was recorded for PREDICT and an associated NHI ethnicity code was identified by merge-match linking on an encrypted NHI number. Agreement between ethnicity measures was assessed by kappa scores and scaled rectangle diagrams. RESULTS: A cohort of 18,239 individuals was linked in both PREDICT and NHI databases. The agreement between ethnicity classifications was reasonably good, with overall kappa coefficient of 0.82. There was better agreement for women than men and agreement improved with age and with time since the PREDICT system has been operational. Ethnic-specific cardiovascular (CVD) hospital admission rates were sensitive to ethnicity coding by NHI or PREDICT; rate ratios for ethnic groups, relative to European, based on PREDICT were attenuated towards the null relative to the NHI classification. CONCLUSIONS: Agreement between ethnicity was moderately good. Discordances that do exist do not have a substantial effect on prevalence-based measures of effect; however, they do on measurement of the admission of CVD. IMPLICATIONS: Different categorisations of ethnicity data from routine (and other) databases can lead to different ethnic-specific estimates of epidemiological effects. There is an imperative to record ethnicity in a rational, systematic and consistent way.

Sugar, dental caries and the incidence of acute rheumatic fever: a cohort study of Maori and Pacific children.

OBJECTIVE: To determine whether dental caries, as an indicator of cumulative exposure to sugar, is associated with the incidence of acute rheumatic fever and chronic rheumatic heart disease, in Maori and Pacific children aged 5 and 6 years at their first dental visit. MATERIALS AND METHODS: A cohort study was undertaken which linked school dental service records of caries with national hospital discharge and mortality records. Cox models were used to investigate the strength of the association between dental caries and rheumatic fever incidence. RESULTS: A total of 20 333 children who were free of rheumatic heart disease at enrolment were available for analysis. During a mean follow-up time of 5 years, 96 children developed acute rheumatic fever or chronic rheumatic heart disease. After adjustment for potential confounders, children with five or more primary teeth affected by caries were 57% (95% CI: 20% to 106%) more likely to develop disease during follow-up, compared to children whose primary teeth were caries free. The population attributable to the risk for caries in this cohort was 22%. CONCLUSIONS: Dental caries is positively associated with the incidence of acute rheumatic fever and chronic rheumatic heart disease in Maori and Pacific children. Sugar intake, an important risk factor for dental caries, is also likely to influence the aetiology of rheumatic fever.

Status of cardiovascular health among adults in a rural area of Northwest China: Results from a cross-sectional study.

The aim of this study was to assess the status of cardiovascular health among a rural population in Northwest China and to determine the associated factors for cardiovascular health.A population-based cross-sectional study was conducted in the rural areas of Hanzhong in Northwest China. Interview, physical examination, and fasting blood glucose and lipid measurements were completed for 2693 adults. The construct of cardiovascular health and the definitions of cardiovascular health metrics proposed by the American Heart Association were used to assess cardiovascular health. The proportions of subjects with cardiovascular health metrics were calculated, adjusting for age and sex. The multiple logistic regression model was used to evaluate the association between ideal cardiovascular health and its associated factors.Only 0.5% (0.0% in men vs 0.9% in women, P = 0.002) of the participants had ideal cardiovascular health, whereas 33.8% (18.0% in men vs 50.0% in women, P < 0.001) and 65.7% (82.0% in men vs 49.1% in women, P < 0.001) of the participants had intermediate and poor cardiovascular health, respectively. The prevalence of poor cardiovascular health increased with increasing age (P < 0.001 for trend). Participants fulfilled, on average, 4.4 (95% confidence interval: 4.2-4.7) of the ideal cardiovascular health metrics. Also, 22.2% of the participants presented with 3 or fewer ideal metrics. Only 19.4% of the participants presented with 6 or more ideal metrics. 24.1% of the participants had all 4 ideal health factors, but only 1.1% of the participants had all 4 ideal health behaviors. Women were more likely to have ideal cardiovascular health, whereas adults aged 35 years or over and those who had a family history of hypertension were less likely to have ideal cardiovascular health.The prevalence of ideal cardiovascular health was extremely low among the rural population in Northwest China. Most adults, especially men and the elderly, had a poor cardiovascular health status. To improve cardiovascular health among the rural population, efforts, especially lifestyle improvements, education and interventions to make healthier food choices, reduce salt intake, increase physical activities, and cease smoking, will be required at the individual, population, and social levels.

Scaled rectangle diagrams can be used to visualize clinical and epidemiological data.

OBJECTIVE: To illustrate scaled rectangle diagrams as a method for displaying clinical and epidemiological attributes (such as symptoms, signs, results of marker tests, disease, or risk factors). These are quantitative Venn diagrams, but using rectangles instead of circles. STUDY DESIGN AND SETTING: The method is illustrated through examples from various data sets with different types of clinical information. RESULTS: Examples drawing on studies of lung disease, rheumatic fever, blood pressure, lipid levels, sudden infant death syndrome, and low birth weight illustrate the different types of relationships between variables that the scaled rectangle approach can reveal (e.g., high- and low-risk groups; dependent, independent, or co-occurring attributes; effects from choice of cutoff; cumulative distributions; and case-control attributes). CONCLUSION: Scaled rectangle diagrams are a novel way to display clinical data. They show clearly the relative frequency of clinical attributes and the extent to which they are shared characteristics. Features are revealed that might otherwise not have been appreciated.

Standard expected years of life lost as a measure of mortality: norms and reference to New Zealand data.

OBJECTIVES: Standard expected years of life lost (SEYLL) is a component of the disability adjusted life year (DALY) measure of disease burden. SEYLL is calculated from the expected remaining years, as specified by a normative survivorship that is derived from a model life table. Because every death has non-zero remaining years, years of life lost are never zero, even in a population that achieves the ideal life expectancy of the model life table itself. As zero is unattainable, what is an acceptable years of life lost? The study calculates norms and examines NZ data against them. METHOD: Using model life tables with expectancy 80 years for men and 82.5 years for women, the years of life lost in cohorts that achieve the model life table expectancy are evaluated. Years of life lost per death and per head of population are considered and the effects of age-standardising, discounting and age-weighting are evaluated. Mortality and Census data are used to compute actual years of life lost in New Zealand, which are compared with the norms. RESULTS: Crude years of life lost per death is about 9-10 years in a population that achieves the model life table distribution. New Zealand European years of life lost are about five years in excess of the 9-10 year norm; Maori about 21 years. The effects of age standardising, using the Segi standard population, give a norm of about 21 years; both Maori and European values are about two years in excess of this figure. CONCLUSIONS: Crude and age-standardised YLLs in New Zealand exceed the ideal set by the model life tables norms, especially so in Maori. Age-standardising has a strong influence on the statistics. IMPLICATIONS: Years of life lost measures need to be considered against the established norms. Unless done so, the measures can appear more adverse than they actually are.

Meningococcal disease and meteorological conditions in Auckland, New Zealand.

OBJECTIVE: The purpose of the study was to explore and model the relationship between meteorological variables and meningococcal disease notifications in Auckland during an ongoing group B meningococcal disease epidemic. METHODS: An ecological study design was used to investigate the relationship between 1,097 notified cases of meningococcal disease from January 1992 to December 1998 among residents of Auckland's three health districts and various meteorological variables. Descriptive epidemiology and Poisson regression modelling were used to describe this relationship. FINDINGS: The study found that the occurrence of meningococcal disease varied with season, increased with high humidity and cooler temperatures and appeared to decline with prolonged periods of heavy rain. Poisson regression analysis showed a significant relationship between the expected number of cases developing meningococcal disease on a given day and season and temperature. DISCUSSION: The results of the modelling analysis provide the initial work for the future development of a predictive tool to forecast the magnitude and duration of the annual peak in meningococcal disease incidence using routine notification data and meteorological recordings, thus allowing for better management of the public health workload and interventions, and the appropriate timing of media campaigns.

Denver screening protocol for blunt cerebrovascular injury reduces the use of multi-detector computed tomography angiography.

BACKGROUND: Blunt cerebrovascular injury (BCVI) occurs in 0.2-2.7% of blunt trauma patients and has up to 30% mortality. Conventional screening does not recognize up to 20% of BCVI patients. To improve diagnosis of BCVI, both an expanded battery of screening criteria and a multi-detector computed tomography angiography (CTA) have been suggested. The aim of this study is to investigate whether the use of CTA restricted to the Denver protocol screen-positive patients would reduce the unnecessary use of CTA as a pre-emptive screening tool. METHODS: This is a registry-based study of blunt trauma patients admitted to Auckland City Hospital from 1998 to 2012. The diagnosis of BCVI was confirmed or excluded with CTA, magnetic resonance angiography and, if these imaging were non-conclusive, four-vessel digital subtraction angiography. RESULTS: Thirty (61%) BCVI and 19 (39%) non-BCVI patients met eligibility criteria. The Denver protocol applied to our cohort of patients had a sensitivity of 97% (95% confidence interval (CI): 83-100%) and a specificity of 42% (95% CI: 20-67%). With a prevalence of BCVI in blunt trauma patients of 0.2% and 2.7%, post-test odds of a screen-positive test were 0.03 (95% CI: 0.002-0.005) and 0.046 (95% CI: 0.314-0.068), respectively. CONCLUSIONS: Application of the CTA to the Denver protocol screen-positive trauma patients can decrease the use of CTA as a pre-emptive screening tool by 95-97% and reduces its hazards.

Alcohol intake, marijuana use, and sleep deprivation on the risk of falls occurring at home among young and middle-aged adults: a case-crossover study.

AIM: This study investigated whether hospitalised fall-related injuries among young and middle-aged adults were associated with short term effects of alcohol intake, marijuana use and sleep deprivation. METHOD: A case-crossover design was used to study 690 adults (aged 20 to 64 years) admitted to public hospitals within 48 hours of a fall-related injury, occurring at home, in three regions of New Zealand during August 2008 to December 2009. A matched-pair interval method of analysis was used to compare alcohol intake, marijuana use and sleep deprivation before the event with similar information in two control periods: 24 hours-before and 1 week-before the time of injury. RESULTS: After adjustment for other paired exposures, the estimated risk of injury was substantially higher after consuming alcohol within the preceding 6 hours, with a dose response gradient. After adjusting for confounding variables, the data did not support a significantly elevated risk of fall-related injury associated with sleep deprivation (<6 hours sleep in the preceding 24 hours), or marijuana use in the preceding 3 hours. CONCLUSION: The findings support the expansion of efforts to reduce the harmful effects of alcohol intake in the home environment.

Treatment monitoring and mortality risk adjustment in anaemic Jehovah's Witnesses.

BACKGROUND: Management of anaemic Jehovah's Witness (JW) patients, who refuse blood transfusion on religious grounds, is challenging. In the published literature, there are few cohort studies that consider causes of mortality in isolation and are lacking in their predictive power. This does not allow clinicians to monitor treatment progress of severely anaemic JW patients and adjust their risk of mortality. The study aims to develop an anaemia-related mortality risk prediction instrument. METHODS: This retrospective cohort study evaluated anaemia-related mortality risk factors of JW patients. JW patients were identified from the records of four major public hospitals in the Auckland and Midlands regions of New Zealand (North Shore, Auckland City, Middlemore and Waikato hospitals) for the period 1998 to 2007 inclusive. The inclusion criteria were age ≥15 years and severe anaemia (haemoglobin concentration ≤80 g/L). Palliative care cancer patients were excluded. RESULTS: Anaemia-related risk factors of mortality for JW patients were identified, weighted and used to construct a mortality risk predictive score (the Hamilton Anaemia Mortality Risk Score (Hamilton AMRS)). This permitted stratification of JW patients into mortality risk groups according to their Hamilton AMRS. It is shown that patients with Hamilton AMRS of 0 to 2 had 4% mortality, patients with Hamilton AMRS of 3 to 4 had 29% mortality, patients with Hamilton AMRS of 5 had 40% mortality and patients with Hamilton AMRS of ≥6 had 67% mortality. CONCLUSION: The Hamilton AMRS allows treatment monitoring of anaemic JW patients and adjustment of their risk of mortality.

Trends in population blood pressure and prevalence, awareness, treatment, and control of hypertension among middle-aged and older adults in a rural area of Northwest China from 1982 to 2010.

OBJECTIVES: To assess trends in average blood pressure levels and prevalence, awareness, treatment, and control of hypertension among adults in a rural area of Northwest China, and to determine associated risk factors. METHODS: Four cross-sectional population-based surveys were conducted between 1982 and 2010 among randomly selected adults in rural areas of Hanzhong, in Northwest China. Data on blood pressure, body mass index, family history of hypertension, and socio-demographic and lifestyle characteristics were collected in similar way by trained investigators in four surveys. Data of 8575 participants aged 35-64 years was analyzed. Averages and proportions were adjusted for age and sex. RESULTS: Average blood pressure in the population has increased since 1982 from 76.9 mm Hg to 79.6 mm Hg in 2010 (diastolic) and from 120.9 to 129.7 mm Hg (systolic). Prevalence of hypertension increased from 18.4% in 1982 to 30.5% in 2010, and awareness of hypertension increased from 16.8% to 38.4% in 2010. Treatment of hypertension increased from 1.0% in 1982 to 17.4% in 2010, and control of hypertension increased from 0.1% in 1982 to 3.5% in 2010. All these gradients were statistically significant (P<0.01 for trend). Population blood pressure and prevalence, awareness and treatment of hypertension were positively associated with increasing age, body mass index and having family history of hypertension. CONCLUSIONS: Average blood pressure levels and the prevalence, awareness, treatment and control of hypertension among adults in rural areas of Hanzhong have increased since 1982. However, awareness, treatment and control rates remain low. Public health programs and practical strategies are required to improve prevention and control of hypertension in rural Northwest China. In particular, attention should be given to the elderly and obese, and to those with a family history of hypertension, while raising awareness and treatment among younger adults.

Association between ambient temperature and blood pressure and blood pressure regulators: 1831 hypertensive patients followed up for three years.

Several studies have suggested an association between ambient air temperature and blood pressure. However, this has not been reliably confirmed by longitudinal studies. Also, whether the reaction to temperature stimulation is modified by other factors such as antihypertensive medication is rarely investigated. The present study explores the relationship between ambient temperature and blood pressure, without and with antihypertensive medication, in a study of 1,831 hypertensive patients followed up for three years, in two or four weekly check ups, accumulating 62,452 follow-up records. Both baseline and follow-up blood pressure showed an inverse association with ambient temperature, which explained 32.4% and 65.6% of variation of systolic blood pressure and diastolic blood pressure (P<0.05) respectively. The amplitude of individual blood pressure fluctuation with temperature throughout a year (a 29 degrees centigrade range) was 9.4/7.3 mmHg. Medication with angiotensin converting enzyme inhibitor benazepril attenuated the blood pressure fluctuation by 2.4/1.3 mmHg each year, though the inverse association of temperature and blood pressure remained. Gender, drinking behavior and body mass index were also found to modify the association between temperature and diastolic blood pressure. The results indicate that ambient temperature may negatively regulate blood pressure. Hypertensive patients should monitor and treat blood pressure more carefully in cold days, and it could be especially important for the males, thinner people and drinkers.

Screening for Mycobacterium tuberculosis infection among healthcare workers in New Zealand: prospective comparison between the tuberculin skin test and the QuantiFERON-TB Gold In-Tube assay.

A cross-sectional study was used to compare the "QuantiFERON-TB Gold In-tube" assay (QFT-GIT) to the Mantoux tuberculin skin test (TST) as a test for Mycobacterium tuberculosis (TB) infection among healthcare workers in Auckland, New Zealand (NZ). New employees who underwent pre-employment interviews between 1 May 2007 and 18 March 2008 were recruited. Participants completed a detailed questionnaire to assess their risk of TB. All participants were tested by the QFT-GIT and TST. Multiple logistic regression analysis was used to correlate positive results with risk factors for TB and previous BCG. None of the 325 participants were found to have active TB. Approximately 67% had been BCG vaccinated. Positive results for each test were associated with residence in a high incidence country [odds ratio (OR)=6.77; p=0.0005 and 4.48; p<0.0001 for QFT-GIT and TST respectively]. Although positive TST results were associated with "high-risk occupational exposure" to TB [OR=4.13; p=0.016], they were also associated with previous BCG vaccination (OR=5.10; p=0.003). Both tests were associated with at least one well described risk factor for TB infection. The association between positive TST and BCG implies that a high percentage of positive TST results occurred due to non-specific cross-reactivity with BCG. Our findings suggest that among low TB prevalence populations with a high rate of BCG vaccination, the QFT-GIT is more specific than the TST although the superior specificity may be at the expense of some sensitivity.