Evelyn McCrum

Physical activity, physical fitness, blood pressure, and fibrinogen in the Northern Ireland health and activity survey.

STUDY OBJECTIVE: To investigate the relationship between physical activity, physical fitness, blood pressure, and fibrinogen. DESIGN: This was a cross sectional population study using a two stage probability sample. SETTING: Northern Ireland. PARTICIPANTS: A sample of 1600 subjects aged 16-74 years from the population of Northern Ireland. MAIN OUTCOME MEASURES: Physical activity profile from computer assisted interview using the Allied Dunbar national fitness survey scales. Physical fitness using estimation of VO2 max by extrapolation from submaximal oxygen uptake while walking on a motor driven treadmill. Systolic and diastolic blood pressure measured with a Hawksley random zero sphygmomanometer. Measurement of fibrinogen using the Clauss method. MAIN RESULTS: There were significant relationships between both current and past activity and blood pressure. These were of a magnitude that would have been clinically significant, but for the fact that, with the exception of the relationship between habitual activity and diastolic pressure (p = 0.03) and past activity and systolic pressure (p = 0.03) in men, they were not sustained after adjustment for the effect of age using analysis of variance. After adjustment for other potentially confounding factors using multiple regression, there was an inverse relationship between systolic blood pressure and past activity in men, so that those with a life-time of participation compared with a life-time of inactivity had a lower systolic blood pressure of 6 mmHg (p < 0.05). There was a highly significant (p < 0.001) inverse association between both systolic and diastolic blood pressure and physical fitness (VO2 max) which was not sustained after adjustment for possible confounding factors. There were relationships between fibrinogen and highest recorded activity (p < 0.001), habitual activity (p < 0.01), and past activity (p < 0.01) in men but no significant relationship in women. The relationship between fibrinogen and activity was no longer sustained after adjustment for possible confounding factors. There was a highly significant (p < 0.001) inverse relationship with physical fitness using VO2 max. This relationship was sustained after adjustment for possible confounding factors in both men (p < 0.05) and women (p < 0.001). CONCLUSIONS: There was a relationship between physical activity, physical fitness, and blood pressure but the relationship was greatly influenced by age. A reduction of 6 mmHg in systolic blood pressure associated with past activity is of clinical significance and supports the hypothesis that physical activity is of benefit in reducing cardiovascular risk. There was a lower level of fibrinogen in those who were most active but this relationship was not significant after adjustment for possible confounding factors. There was also a lower level of fibrinogen those who were most fit (VO2 max) and this relationship persisted even after adjustment for possible confounding factors.

Sleep complaints and risk factors for excessive daytime sleepiness in adult males in Northern Ireland

The prevalence of sleep complaints in Northern Ireland is unknown. Sleep disruption can result in excessive daytime sleepiness (EDS), with significant socioeconomic consequences. The aim of this study was to assess the prevalence of sleep complaints and to determine risk factors for EDS in a Northern Irish community. From an urban and rural community of 499 111 people, a random sample of 3391 adult men were sent a questionnaire by mail. Questions were asked regarding sleep, EDS and medical history. There were 2364 completed questionnaires returned (response rate 70%). The mean age of respondents was 46.0 years (range 18–91 years). 26.7% of men were not satisfied with their usual night’s sleep and 68% of men woke up at least once during the night. Based on pre‐defined criteria, 24.6% of the population had insomnia and 19.8% had EDS. The strongest risk factor identified for EDS was a history of snoring loudly (odds ratio 2.62; 95% CI 1.82–3.77). Other risk factors included ankle swelling, feeling sad or depressed stopping sleep, experiencing vivid dreams while falling asleep, waking up feeling unrefreshed and age > 35 years. The prevalence rates of sleep complaints and EDS in this community‐based study is high, although this does depend directly on the criteria used to define insomnia and EDS. Recognition of risk factors for EDS may help to identify and treat those affected.

Smoking, atopy and certain furry pets are major determinants of respiratory symptoms in children: the International Study of Asthma and Allergies in Childhood Study (Ireland).

Background Environmental, cultural and health care differences may account for variation among countries in the prevalence of asthma and respiratory symptoms in teenagers.

Association between serum levels of total IgA and IgA class endomysial and antigliadin antibodies: implications for coeliac disease screening.

Background: Patients with selective immunoglobulin A (IgA) deficiency and coeliac disease, an established association, lack serum IgA class antigliadin and endomysial antibodies (AGA, EmA). Diagnostic protocols relying on AGA and EmA to select patients for small bowel biopsies will not identify these patients. Objective: To determine whether total IgA should be routinely measured in patients suspected of having coeliac disease as a supplementary screening test before biopsy. Design: Prospective measurement of IgA, AGA and EmA in patients undergoing small bowel biopsy for suspected coeliac disease. Patients: We studied 318 patients suspected of having coeliac disease. Sera from 1959 controls in a random population sample were assayed as controls. Results: Thirty‐one (10%) patients had villous atrophy, of whom 27 (87%) had EmA. Five (2%) of the 318 patients had undetectable total IgA (<0.07 g/l): two (40%) of these five had villous atrophy in the setting of negative EmA. Use of undetectable IgA as a selection criterion for small bowel biopsy as well as positive EmA would have improved sensitivity from 87% (27/31) for EmA alone to 94% (29/31), with a fall in positive predictive value from 100% (27/27) to 91% (29/32), but would have maintained high specificity and negative predictive value. Serum IgA was undetectable in 5 (4%) of 117 patients with AGA in the range 0‐10 ELISA units (EU) compared with none of 201 with higher AGA (P = 0.007, Fishers exact test). Compared with controls who had AGA 0‐10EU, patients were more likely to have undetectable IgA (5/117 (4%) vs. 3/706 (0.4%): P = 0.005). Overall, the median IgA in patients with AGA 0‐10 EU was lower than for those with AGA >10EU (1.89 g/l vs. 2.34g/l, P < 0.001). Conclusion: There is an association between IgA deficiency and low/negative EmA/AGA. Routine measurement of total serum IgA in patients suspected of having coeliac disease, either with EmA or where AGA is low, improves selection of patients for small bowel biopsy.

Physical activity, lipids, apolipoproteins, and Lp(a) in the Northern Ireland Health and Activity Survey

In a cross-sectional study using a two-stage probability sample (N = 1,600) of the population of Northern Ireland, there was an inverse association between the highest recorded recent activity and total cholesterol (P < or = 0.01), LDL (P < or = 0.01), triglyceride (P < or = 0.05) and Chol:HDL ratio (P < or = 0.001) in males, and total cholesterol (P < or = 0.001), LDL (P < or = 0.001), and triglyceride (P < or = 0.01) in females; between habitual activity and HDL (P < or = 0.05) in males and total cholesterol (P < or = 0.05) and triglyceride (P < or = 0.01) in females. There was a relationship between the highest recorded activity and apoAI (P < or = 0.01) and apoB (P < or = 0.01) in males and with apoB (P < or = 0.001) in females; between habitual activity and apoAI (P < or = 0.01) and apoAII (P < or = 0.05) in males and apoB (P < or = 0.01) in females; between past activity and Lp(a) in females (P < or = 0.05). After adjustment for possible confounding factors, total cholesterol (P < or = 0.05) and LDL (P < or = 0.05) were unexpectedly higher in males who were active throughout life. Total cholesterol (P < or = 0.05) and LDL (P < or = 0.001) were higher in females with highest recorded activity and triglycerides lower (P < or = 0.05) in those habitually active. An association between highest recorded activity and apoAI (P < or = 0.01), and past activity and apoAI:apoB ratio (P < or = 0.05) was shown in males and in females, after adjustment, and between apoB (P < or = 0.05) and highest recorded activity.

Randomised controlled trial of the READER method of critical appraisal in general practice

Abstract Objective: To evaluate the READER model for critical reading by comparing it with a free appraisal, and to explore what factors influence different components of the model. Design: A randomised controlled trial in which two groups of general practitioners assessed three papers from the general practice section of the BMJ. Setting: Northern Ireland. Subjects: 243 general practitioners. Main outcome measures: Scores given using the READER model (Relevance, Education, Applicability, Discrimination, overall Evaluation) and scores given using a free appraisal for scientific quality and an overall total. Results: The hierarchical order for the three papers was different for the two groups, according to the total scores. Participants using the READER method (intervention group) gave a significantly lower total score (P⩽0.01) and a lower score for the scientific quality (P⩽0.0001) for all three papers. Overall more than one in five (22%), and more men than women, read more than 5 articles a month (P⩽0.05). Those who were trainers tended to read more articles (P⩽0.05), and no trainers admitted to reading none. Overall, 58% (135/234) (68% (76/112) of the intervention group) believed that taking part in the exercise would encourage them to be more critical of published articles in the future (P⩽0.01). Conclusion: Participants using the READER model gave a consistently lower overall score and applied a more appropriate appraisal to the methodology of the studies. The method was both accurate and repeatable. No intrinsic factors influenced the scores, so the model is appropriate for use by all general practitioners regardless of their seniority, location, teaching or training experience, and the number of articles they read regularly.

Antioxidants, but not B-group vitamins increase the resistance of low-density lipoprotein to oxidation: a randomized, factorial design, placebo-controlled trial.

We have conducted an intervention trial to assess the effects of antioxidants and B-group vitamins on the susceptibility of low-density lipoprotein (LDL) to oxidation. A total of 509 men aged 30-49 from a local workforce were screened for total plasma homocysteine. The 132 selected (homocysteine concentration > or = 8.34 mumol/l) men were randomly assigned, using a factorial design, to one of four groups receiving supplementation with B group vitamins alone (1 mg folic acid, 7.2 mg pyridoxine, 0.02 mg cyanocobalamin), antioxidant vitamins (150 mg ascorbic acid, 67 mg alpha-tocopherol, 9 mg beta-carotene), B vitamins with antioxidant vitamins, or placebo. Intervention was double-blind. A total of 101 men completed the 8-week study. The lag time of LDL isolated ex vivo to oxidation (induced by 2 mumol/l cupric chloride) was increased in the two groups receiving antioxidants whether with (6.88 +/- 1.65 min) or without (8.51 +/- 1.77 min) B-vitamins, compared with placebo (-2.03 +/- 1.50) or B-vitamins alone (-3.34 +/- 1.08) (Mean +/- S.E., P < 0.001). Antibodies to malondialdehyde (MDA) modified LDL were also measured, but there were no significant changes in titers of these antibodies in any group of subjects whether receiving antioxidants or not. Contrast analysis showed that there was no interaction between antioxidants and B-group vitamins. This study indicates that while B-group vitamins lower plasma homocysteine they do not have an antioxidant effect. Thus B-group vitamins and antioxidants appear to have separate, independent effects in reducing cardiovascular risk.

Physical activity, physical fitness and respiratory function - Exercise and respiratory function

The aim of the study was to establish patterns of respiratory function in Northern Ireland and to examine the relationship between physical activity, physical fitness and respiratory function.We identified 1600 adults over 16 yr using 2 stage probability sampling. Physical activity was measured using a questionnaire, physical fitness from oxygen uptake while walking on a treadmill, and respiratory function using spirometry. The main outcome measures were a physical activity profile based on computer assisted interview, physical fitness by predicted VO2max, Forced Vital Capacity (FVC) and Forced Expiratory Volume (FEV1). We found that the main findings were of relationships between activity and FVC and FEV 1 which remained after adjustment for possible confounders in men, and between fitness and FVC and FEV 1 in both men and women although these were not sustained after adjustment for possible confounders.

Dietary patterns in the Belfast MONICA Project.

Northern Ireland provides a centre for the World Health Organization co-ordinated MONICA Project (multinational monitoring of trends and determinants in cardiovascular disease; World Health Organization 1983). This is a 10-year study which aims to relate trends in incidence (mortality and morbidity) to changes in the levels of the major risk factors measured in three independent community surveys. The Belfast MONICA Project began in 1983 and will run until the end of 1992. Apart from the local dimensions, adherence to a common protocol means that it will be possible to review, in parallel, the results from the thirty or so participating centres from around the world. Some countries are showing rapidly increasing incidence of ischaemic heart disease, whereas in others, such as North America and Australia the disease’s mortality has almost halved over the past two decades. The EURONUT Dietary Survey was one of a number of nutrition surveys carried out by the Belfast MONICA Project. Other studies include INTERSALT (a multi-centre comparison relating salt excretion to mean blood pressure in the population), CARDIAC (a Japanese study of salt and hypertension) and a study of the role of antioxidants in coronary heart disease. In 1986, when the survey work described in the present report was carried out, Northern Ireland lay at the top of the world mortality league for ischaemic heart disease in males (Registrar General for Northern Ireland, 1987), and came second only to Scotland in females (Registrar General for Scotland, 1987). Serum lipid levels are of crucial importance in atherogenesis and these in turn are related to dietary intake, a fact well established by pioneer studies such as the Seven Countries Study. Obviously, international comparisons of diet within the MONICA Project centres would have been of great interest, but unfortunately, because of the wide disparity in diets across the world it was considered impracticable to attempt to establish a uniform dietary surveillance system. However, an adequate assessment of dietary intake in the MONICA centres within Europe was obviously feasible. EURONUT, a concerted action project on nutrition in the European Community, deals with many aspects of population nutrition. A joint EURONUT/MONICA Project study was set up (Knuiman et al. 1985) to examine the dietary habits in the European populations with special regard to cardiovascular diseases. As the study focused on the relationship between changes in diet and changes in coronary heart disease incidence with time, this could only realistically be carried out in middle-aged men as they alone would generate a sufficient number of events to allow

Physical fitness, lipids, and apolipoproteins in the Northern Ireland Health and Activity Survey.

The objective of this study was to investigate the relationship between physical fitness, lipids, and apolipoproteins in a cross-sectional study using a two-stage probability sample of the population of Northern Ireland. The main outcome measures were physical fitness using VO2max estimated by extrapolation from submaximal oxygen uptake while walking on a motor driven treadmill, and total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, HDL2 and HDL3, and Lp(a). There were no significant relationships with fitness, after adjustment for possible confounders, with the exception of a positive relationship with HDL2 in males (P < or = 0.01) and Lp(a) in females (P < or = 0.05). There was also a relationship between physical fitness and HDL:apo AI ratio in males and females after adjustment for possible confounders (P < or = 0.05). We concluded that there were few relationships between lipid parameters and physical fitness after adjustment for possible confounders. The relationship between physical fitness and Lp(a) in females suggests a benefit associated with physical fitness and the relationship between physical fitness and HDL:apo AI ratio was in keeping with improved HDL cholesterol transport.