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Biomedical subjects

Thomas G Pickering

Publications and source records attributed to Thomas G Pickering.

At least 73 records · Page 4Linked to original sources
PubMed2003

Life-course exposure to job strain and ambulatory blood pressure in men.

This 1985-1995 study was designed to assess the association between blood pressure (measured by using an ambulatory monitor) and history of exposure to job strain. Items from the Job Content Questionnaire were completed by 213 employed men, aged 30-60 years at entry into the Work Site Blood Pressure Study in New York City, New York, for each previous job they had held. The systolic blood pressure of men employed for >/=25 years who were exposed to job strain for 50% of their work life was 4.8 mmHg (95% confidence interval: -3.7, 13.4) higher at work and 7.9 mmHg (95% confidence interval: 0.8, 15.0) higher at home than that of men with no past exposure, independent of current exposure. Evidence was inconsistent for the hypothesis of rapid induction of/recovery from the effects of job strain on blood pressure, and there was little effect of past job strain on diastolic blood pressure. These findings provide some support for the hypothesis of an effect of cumulative burden of exposure to job strain on systolic blood pressure.

Adult↗
PubMed2003

Morning surge in blood pressure as a predictor of silent and clinical cerebrovascular disease in elderly hypertensives: a prospective study.

BACKGROUND: Cardiovascular events occur most frequently in the morning hours. We prospectively studied the association between the morning blood pressure (BP) surge and stroke in elderly hypertensives. METHODS AND RESULTS: We studied stroke prognosis in 519 older hypertensives in whom ambulatory BP monitoring was performed and silent cerebral infarct was assessed by brain MRI and who were followed up prospectively. The morning BP surge (MS) was calculated as follows: mean systolic BP during the 2 hours after awakening minus mean systolic BP during the 1 hour that included the lowest sleep BP. During an average duration of 41 months (range 1 to 68 months), 44 stroke events occurred. When the patients were divided into 2 groups according to MS, those in the top decile (MS group; MS > or =55 mm Hg, n=53) had a higher baseline prevalence of multiple infarcts (57% versus 33%, P=0.001) and a higher stroke incidence (19% versus 7.3%, P=0.004) during the follow-up period than the others (non-MS group; MS <55 mm Hg, n=466). After they were matched for age and 24-hour BP, the relative risk of the MS group versus the non-MS group remained significant (relative risk=2.7, P=0.04). The MS was associated with stroke events independently of 24-hour BP, nocturnal BP dipping status, and baseline prevalence of silent infarct (P=0.008). CONCLUSIONS: In older hypertensives, a higher morning BP surge is associated with stroke risk independently of ambulatory BP, nocturnal BP falls, and silent infarct. Reduction of the MS could thus be a new therapeutic target for preventing target organ damage and subsequent cardiovascular events in hypertensive patients.

Aged↗
PubMed2003

beta-Blockers in hypertension-the emperor has no clothes: an open letter to present and prospective drafters of new guidelines for the treatment of hypertension.

Over the past decade, national and international guidelines have proposed beta-blockers to be used on an equal footing with diuretics for initial therapy of hypertension. This preferred status was supposedly based on evidence documenting a reduction in morbidity and mortality with beta-blocker therapy in hypertension. We systematically analyzed all available outcome studies and found no evidence that beta-blocker based therapy, despite lowering blood pressure, reduced the risk of heart attacks or strokes. Despite the inefficacy of beta-blockers, the incidence of adverse effects is substantial. In the MRC study, for every heart attack or stroke prevented, three patients withdrew from atenolol because of impotence, and another seven withdrew because of fatigue. Thus the risk/benefit ratio of beta-blockers is characterized by lack of efficacy and multiple adverse effects. Given that many thorough, prospective, randomized trials attest to efficacy and safety of diuretics, calcium antagonists, ACE inhibitors, and angiotensin receptor inhibitors, the time has come to admit that beta-blockers should no longer be considered appropriate for first-line therapy in uncomplicated hypertension.

Adrenergic beta-Antagonists↗
PubMed2003

Clinical implication of morning blood pressure surge in hypertension.

Cardiovascular events occur most frequently in the morning. The morning surge in blood pressure may be associated with hypertensive target organ damage and subsequent cardiovascular risk in hypertensive patients. In our prospective study on elderly hypertensive patients, the morning blood pressure surge (defined as the increase from the lowest blood pressure during sleep to the average of the first 2 h after waking) was significantly associated with silent hypertensive cerebrovascular disease and subsequent stroke risk. This association was independent of age and 24-h ambulatory blood pressure levels. In addition, even after controlling for these factors and status of silent cerebrovascular disease, the contribution of the morning blood pressure surge remained significant, and a 10 mmHg increase in systolic morning blood pressure surge increase the stroke risk by 22%. A related factor is orthostatic hypertension, which might be associated with increased sympathetic activity, and which is significantly associated with an increase in morning blood pressure surge and ambulatory blood pressure variability. A possible implication is that, in addition to strict blood pressure control, antihypertensive medication that targets exaggerated morning blood pressure may achieve more effective prevention of cardiovascular events in hypertensive patients.

Blood Pressure↗
PubMed2003

What will replace the mercury sphygmomanometer?

Mercury sphygmomanometers are gradually being phased out, not because of any technological advances but because of environmental concerns. While mercury is still accepted as the 'gold standard' for routine clinical measurement, it suffers from two deficiencies: poor observer technique, and problems due to poor maintenance of the devices. At the same time, there is no generally accepted alternative; the most widely advocated candidates are aneroid or oscillometric devices. Oscillometric devices have the advantages of eliminating observer error and mechanical drift, but it is suggested that the inherent limitations of the oscillometric method mean that it cannot become the gold standard for clinical measurement in individual patients. Aneroid monitors have been found in practice to be frequently deficient, and are subject to the same deficiencies in observer technique as mercury devices. Two possible but so far untested techniques are a 'hybrid' sphygmomanometer, whereby the mercury column is replaced by an electronic transducer and display, and the wideband recording technique, which has the potential of using the same basic principle as the auscultatory technique, while eliminating the human observer.

Blood Pressure Determination↗
PubMed2003

Disasters and the heart: a review of the effects of earthquake-induced stress on cardiovascular disease.

There is growing evidence that stress contributes to cardiovascular disease. Chronic stress contributes to the atherosclerotic process through increased allostatic load, which is mediated by the neuroendocrine and immune systems (sympathetic nervous system and hypothalamus-pituitary adrenal axis) and related chronic risk factors (insulin resistance syndrome, hypertension, diabetes, and hyperlipidemia). In addition, acute stress can trigger cardiovascular events predominantly through sympathetic nervous activation and potentiation of acute risk factors (blood pressure increase, endothelial cell dysfunction, increased blood viscosity, and platelet and hemostatic activation). Earthquakes provide a good example of naturally occurring acute and chronic stress, and in this review we focus mainly on the effects of the Hanshin-Awaji earthquake on the cardiovascular system. The Hanshin-Awaji earthquake resulted in a 3-fold increase of myocardial infarctions in people living close to the epicenter, particularly in women, with most of the increase occurring in nighttime-onset events. There was also a near doubling in the frequency of strokes. These effects may be mediated by changes in hemostatic factors, as demonstrated by an increase of D-dimer, von Willebrand factor, and tissue-type plasminogen activator (tPA) antigen. Blood pressure also increased after the earthquake, and was prolonged for several weeks in patients with microalbuminuria.

Cardiovascular Diseases↗
PubMed2003

Lower socioeconomic status among men in relation to the association between job strain and blood pressure.

OBJECTIVES: This study attempted to determine whether the association between job strain (high job demands plus low job control) and blood pressure among men varies by socioeconomic status. METHODS: The cross-sectional associations between job strain and ambulatory blood pressure, by level of education, occupational status, and income, and the interaction between job strain and these measures of socioeconomic status were assessed by multiple linear regression, adjusted for age, race or ethnicity, body mass index, alcohol use, smoking, standing position, and worksite for 283 men, aged 30-60 years, from eight worksites in New York City. RESULTS: A substantial association between job strain and work ambulatory blood pressure was found among men with lower socioeconomic status, ranging from 2.7-11.8 mm Hg systolic to 1.9-6.1 mm Hg diastolic blood pressure, depending upon the measure of socioeconomic status examined. However, in the groups with high socioeconomic status, the association between job strain and ambulatory blood pressure at work was much smaller, the range in blood pressure being 0-5.3 (systolic) and 0.2-2.1 (diastolic) mm Hg. Two of the 10 tests of the interaction between job strain and socioeconomic status had a P-value of <0.05. CONCLUSIONS: These data provide evidence that the relationship between job strain and blood pressure is greater among men with lower socioeconomic status.

Adult↗
PubMed2003

Abnormal nocturnal blood pressure falls in elderly hypertension: clinical significance and determinants.

Abnormal patterns of diurnal blood pressure variation have been reported to be related to advanced target organ damage and poor cardiovascular prognosis. We studied silent cerebrovascular disease and stroke events in older Japanese patients with different nocturnal blood pressure dipping. There was a J-shaped relationship of nocturnal dipping status with silent cerebral infarcts detected by brain magnetic resonance imaging at baseline, and with stroke incidence during the follow-up period. The extreme-dippers (with marked nocturnal blood pressure dipping) and the risers (with higher nocturnal blood pressure than awake blood pressure) had a higher prevalence of silent cerebral infarcts and a poorer stroke prognosis than those with appropriate nocturnal blood pressure dipping (dippers). The extreme-dippers tended to have predominant systolic hypertension and increased blood pressure variability. Several factors affect the diurnal blood pressure variation pattern. The non-dipping pattern is associated with autonomic nervous dysfunction and poor sleep quality due to nocturnal behavior and sleep apnea. The extreme-dippers might have increased arterial stiffness with reduced circulating blood volume in addition to an excessive morning surge due to alpha-adrenergic hyperactivity. Anti-hypertensive medication that normalizes the diurnal blood pressure variation might improve the cardiovascular prognosis in high-risk hypertensive patients.

Aged↗
PubMed2002

Principles and techniques of blood pressure measurement.

The gold standard for clinical blood pressure measurement continues to be readings taken by a physician using a mercury sphygmomanometer, but this is changing as mercury is gradually being phased out. The oscillometric technique, which primarily detects mean arterial pressure, is increasingly popular for use in electronic devices. Other methods include ultrasound (used mainly to detect systolic pressure) and the finger cuff method of Penaz, which can record beat-to-beat pressure noninvasively from the finger. The preferred location of measurement is the upper arm, but errors may occur because of changes in the position of the arm. Other technical sources of error include inappropriate cuff size and too rapid deflation of the cuff. Clinic readings may be unrepresentative of the patient's true blood pressure because of the white coat effect, which is defined as the difference between the clinic readings and the average daytime blood pressure. Patients with elevated clinic pressure and normal daytime pressure are said to have white coat hypertension. There are three commonly used methods for measuring blood pressure for clinical purposes: clinic readings, self-monitoring by the patient at home, and 24-hour ambulatory readings. Self-monitoring is growing rapidly in popularity and is generally carried out using electronic devices that work on the oscillometric technique. Although standard validation protocols exist, many devices on the market have not been tested for accuracy. Such devices can record blood pressure from the upper arm, wrist, or finger, but the arm is preferred. Twenty-four-hour ambulatory monitoring has been found to be the best predictor of cardiovascular risk in the individual patient and is the only technique that can describe the diurnal rhythm of blood pressure accurately. Ambulatory monitoring is mainly used for diagnosing hypertension, whereas self-monitoring is used for following the response to treatment. Different techniques of blood pressure measurement may be preferred in certain situations. In infants the ultrasound technique is best, whereas in pregnancy and after exercise the diastolic pressure may be hard to measure using the conventional auscultatory method. In obese subjects it is important to use a cuff of the correct size.

Age Factors↗
PubMed2002

Incomplete benefit of antihypertensive therapy on stroke reduction in older hypertensives with abnormal nocturnal blood pressure dipping (extreme-dippers and reverse-dippers).

To determine whether the benefits of antihypertensive treatment vary according to dipper status, 811 asymptomatic elderly Japanese hypertensives underwent 24-h ambulatory blood pressure monitoring. During a mean follow-up period of 41 months, 32 stroke events were observed in patients who remained nonmedicated (n = 385), and in 27 patients in the medicated group (n = 426), indicating a 24% lower rate of stroke as a result of antihypertensive therapy. Patients were divided into a white-coat hypertensive (WCHT) group (ambulatory blood pressure <130/80 mm Hg; n = 236) and a sustained hypertensive (SHT) group (n = 575). Sixty-one percent of SHT and 32% of WCHT patients were being medicated. In the SHT group, the stroke rates were 12.4% in nonmedicated and 7.4% in medicated group (P =.04), whereas in the WCHT group the stroke rates were 2.5% in nonmedicated and 1.3% in medicated group (P = not significant). The SHT were further classified according to their nocturnal systolic blood pressure (BP) decrease, as follows: 97 extreme-dippers with >20% nocturnal systolic BP decrease; 230 dippers with >10% but <20% decrease; 185 nondippers with >0% but <10% decrease; 63 reverse-dippers with <0% decrease. In the dipping groups of SHT, the stroke rates were similar according to medication versus no-medication in extreme-dippers (12% v 13%), and reverse-dippers (23% v 22%), but in nondippers there was a significantly lower rate (by 65%, P =.038) in the medicated (4.4%) than the nonmedicated (13%) groups. In dippers, the stroke rate was also lower in the medicated than the nonmedicated patients (4.7% v 8.8%), a decrease of 47% (P =.217), although the difference was not significant. In conclusion, in older SHT subjects, antihypertensive therapy using clinic BP may be less effective for the groups with extremely abnormal diurnal BP patterns (extreme-dippers and reverse-dippers) than those with relatively normal patterns (dippers and nondippers). Patients with WCHT also showed no benefit.

Aged↗
PubMed2002

Validity and reliability of a work history questionnaire derived from the Job Content Questionnaire.

Job design risk factors for hypertension and heart disease have often been assessed by the Job Content Questionnaire (JCQ). Job characteristics are typically assessed only once, however, which can result in misclassification and bias results toward the null. Newer approaches, which assess job characteristics over a working life, are hampered by the need to ask numerous questions about each job, increasing survey length and potentially reducing response rates. Participants in the Work Site Blood Pressure Study, a prospective study of psychosocial factors and ambulatory blood pressure, completed the JCQ about their current jobs. At later dates, 213 employed men, a subset of the original cohort, retrospectively completed the Work History Questionnaire (WHQ), a short version of the JCQ, for each past job. The WHQ exhibited moderate validity for assessing past job characteristics, a weak association with systolic blood pressure, and expected patterns of change over time. Thus, it may be a valuable tool for measuring the health effects of historical job characteristics, which often change over time.

Adult↗