Biomedical subjects

David A Leon

Publications and source records attributed to David A Leon.

41 records · Page 3Linked to original sources

PubMed2004

The Aberdeen Children of the 1950s cohort study: background, methods and follow-up information on a new resource for the study of life course and intergenerational influences on health.

In this paper we introduce and describe in detail an addition to the UK's population-based resources for the investigation of biological and social influences on health across the life course and between generations: the Aberdeen Children of the 1950s study. We also provide an account of postwar Aberdeen when study members were growing up, report on findings of analyses of data from the original survey on which this study is based and its follow-up, assess the strengths and limitations of the study, and outline current and future research directions. This cohort comprises individuals born in Aberdeen, Scotland (UK) between 1950 and 1956, and is derived from 15 thousand subjects who took part in the Aberdeen Child Development Survey, a cross-sectional study of 'mental subnormality' (learning disability) in a population of all children who were attending Aberdeen primary schools in December 1962. Data collection included information on birthweight, gestational age, childhood height and weight, tests of cognition and behavioural disorder, and a range of multilevel socio-economic indicators. In 1998 we began the process of revitalising this cohort (now termed the Aberdeen Children of the 1950s study). We have been successful in ascertaining the current vital status and whereabouts of 98.5% of a target population of 12 150 subjects (6276 males, 5874 females) with full baseline data. The large majority (81%) of study participants still reside in Scotland and many (73%) have remained in the Grampian region which incorporates Aberdeen. At the present time, a total of almost 500 subjects are known to have died. Linkages to hospital admissions and other health endpoints captured through the Scottish Morbidity Records system have been completed. This includes an intergenerational linkage to approximately eight thousand deliveries in Scotland occurring to female members of the study population. A postal questionnaire to all traced surviving cohort members has also been distributed.

Child↗

PubMed2002

Secular trends in mortality by stroke subtype in the 20th century: a retrospective analysis.

BACKGROUND: Since both cerebral infarction and coronary heart disease are caused by atherosclerosis, they would be expected to have similar secular trends in mortality. Because differential diagnosis of stroke subtype on routine death certificates is inaccurate, we aimed to estimate secular trends in cerebral infarct and haemorrhage throughout the 20th century, for England and Wales, with data from autopsy studies. METHODS: We calculated the ratio of cerebral infarct to cerebral haemorrhage from all available sources of autopsy data from the 20th century. These data were used to estimate the ratio of cerebral infarct to haemorrhage for every year, and hence to estimate rates of cerebral infarct and cerebral haemorrhage from the total stroke mortality rate, obtained from the UK Office for National Statistics. FINDINGS: Data about stroke subtypes from autopsies were available from 1932 to 1999. The ratio of cerebral infarct to cerebral haemorrhage increased fourfold from 0.5 in the 1930s to 2.0 by the 1990s; most of the increase took place between the 1930s and the 1970s. Estimated secular trends suggested that there was a steady fall in mortality from cerebral haemorrhage throughout the 20th century, whereas mortality from cerebral infarct increased to a peak in the 1970s and then fell. Trends in estimated cerebral infarct mortality closely matched those for coronary heart disease mortality. INTERPRETATION: The closely related trends in cerebral infarct and coronary heart disease suggest common causes, but the very different trend in cerebral haemorrhage shows that its cause probably differs importantly from these conditions.

Adult↗

PubMed2002

Fetal growth and systolic blood pressure in young adulthood: the Swedish Young Male Twins Study.

The objective was to test the fetal origins hypothesis by examining the association between fetal growth and systolic blood pressure in a large cohort of adult male twins of known zygosity. This cohort study is based on a record linkage of routinely collected data from the Swedish Medical Birth Registry, the Swedish Military Conscription Registry and a mailed questionnaire. It comprises 886 pairs of same-sex male twins born in Sweden in 1973-79 for whom data were available on size at birth and systolic blood pressure, height and weight at age 17-19 years. Based on self-reported similarity of appearance in childhood, 384 twin pairs were classified as monozygotic (MZ), 269 as dizygotic (DZ) and 233 as of uncertain zygosity (XZ). Differences in systolic blood pressure within and between twin pairs were analysed in relation to birthweight and birthweight-for-gestational-age z-score using random effects linear models. Within twin pairs, a 1 kg difference in birthweight was associated with a difference of -1.30 mmHg in systolic blood pressure [95% confidence interval -4.15, +1.54] for MZ twins and +0.14 [-3.49, +3.76] for DZ twins; for all twins combined it was -0.21 [-2.13, +1.71]. Between twin pairs, a 1 kg difference in birthweight was associated with a difference of -2.68 mmHg in systolic blood pressure [-4.95, -0.42] for MZ twins and +0.28 [-2.35, +2.91] for DZ twins; for all twins combined -1.68 [-3.15, -0.22]. All these estimates included adjustment for age, year and conscription centre of examination, gestational age and height and weight at conscription. These results provide little support for the fetal origins hypothesis. The estimates of the within-pair effect in MZ twins and their wide confidence intervals (including zero) cannot exclude the existence of common genetic mechanisms, but are also not inconsistent with an in utero programming effect. This study highlights some methodological problems with twin studies.

Adolescent↗

PubMed2002

Socio-economic position and coronary heart disease risk factors in children and young people. Evidence from UK epidemiological studies.

BACKGROUND: Coronary heart disease (CHD) is a condition with its origin in early life. In adults, CHD and its risk factors show clear socio-economic gradients. The aim of the present review is to collate published evidence to assess if these risk factor gradients are also apparent in young people in the UK. METHODS: Pertinent publications were identified in four ways: i) a systematic search of PUBMED from its inception in January 1966 until October 2000; ii) scanning the reference sections of identified publications; iii) searching the authors' own files; and iv) contacting experts in the field. RESULTS: Of eleven CHD risk factors, consistent evidence concerning the association in child- and early adulthood with socio-economic position was evident for cigarette smoking, birth weight, adiposity (in young adults), height, and some aspects of diet, particularly fat and fibre consumption. As in UK adults, the most favourable levels of these risk factors were seen in young people from socially advantaged backgrounds. For the other variables associated with CHD--physical inactivity/low cardiorespiratory fitness, blood pressure, blood cholesterol, adiposity (in children), and some emerging risk factors (C-reactive protein, homocysteine, fibrinogen)--there was little evidence of any clear association with socio-economic level. CONCLUSIONS: While social variation is seen in some CHD risk factors in young people, further data are needed to fully explore if this is also the case for others. This issue could be addressed by analysing some existing but unutilized survey data from the UK.

Adolescent↗

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INTERHEART.

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Alcohol Drinking↗