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Biomedical subjects

D A Leon

Publications and source records attributed to D A Leon.

At least 55 records · Page 3Linked to original sources
PubMed1997

Size at birth and hypertension in longitudinally followed 50-70-year-old men.

We investigated the relationship between weight at birth and the prevalence of hypertension (defined as treatment and/or systolic blood pressure > 160 mmHg) at ages 50, 60 and 70 years in a cohort of Swedish men followed longitudinally, in which we had previously found a strong inverse association of birthweight with blood pressure at age 50. In men of above median adult height (> 176 cm), a 1000 g decrease in birthweight was associated with an odds ratio for hypertension of 2.53 (95% CI 1.10, 5.85) at age 50, 1.63 (95% CI 0.97, 2.72) at 60 and 1.72 (95% CI 1.10, 2.69) at 70. As the overall prevalence of hypertension increased steeply with age, the absolute difference in the risk of hypertension between those of low and high birthweight increased with age. In men of below median height, birthweight was not significantly associated with blood pressure at any age. Small size at birth is associated with hypertension at 50, 60 and 70 years in men of a high growth potential. The strength of the relationship between birthweight and hypertension does not increase from 50 to 70 years, although the risk of hypertension attributable to low birthweight does increase with age.

Age Factors↗
PubMed1996

History of childbearing and colorectal cancer risk in women aged less than 60: an analysis of Swedish routine registry data 1960-1984.

Data from a computerised linkage between the Swedish Cancer Registry and the Fertility Registry were used to study the influence of reproductive history on the risk of colorectal cancer in women aged less than 60, in the period 1960 to 1984. A "nested" case-control design was used with 1,415 colon cancer cases and 733 rectal cancer cases, and 7,073 and 3,665 age-matched controls, respectively. Conditional logistic regression was employed to study the independent effects of parity, age at first birth and years since last birth on the risk of colorectal cancer. High parity was associated with reduced risk in women older then 50 years at diagnosis, both for the colon as a whole and for colon subsites. Women having had 5 children or more had an odds of colon cancer of 0.44 (95% confidence interval 0.24-0.82) relative to that of nulliparous woman. Contrary to the hypothesis advanced by McMichael and Potter (J. Nat. Cancer Inst., 75, 185-191 [1985]), which predicted a strong protective effect of parity in the proximal compared to the distal colon, we found the reverse. Increasing years since last birth seemed to be associated with a reduced risk of rectal cancer. A significant positive trend with increasing age at first birth was suggested with respect to distal colon cancer and rectal cancer risk. The mutually adjusted effects of the reproductive variables under study were similar to the unadjusted effects. Our data suggest that increasing parity is associated with a decline in risk of colon cancer but not rectal cancer, although the association with colon cancer is restricted to women aged 50 or more. The effects of age at first birth and years since last birth are not consistent or pronounced.

Adult↗
PubMed1996

Failure to realise growth potential in utero and adult obesity in relation to blood pressure in 50 year old Swedish men.

OBJECTIVES: To clarify the type of fetal growth impairment associated with increased blood pressure in adult life, and to establish whether this association is influenced by obesity and is mediated through impairment of insulin action. DESIGN: Cross sectional survey with retrospective ascertainment of size at birth from obstetric archives. SUBJECTS: 1333 men resident in Uppsala, Sweden, who took part in a 1970 study of coronary risk factors at age 50 and for whom birth weight was traced. MAIN OUTCOME MEASURES: Systolic and diastolic blood pressure at age 50. RESULTS: In the full study population for a 1000g increase in birth weight there was a small change in systolic blood pressure of -2.2mmHg (95% confidence interval -4.2 to - 0.3mmHg) and in diastolic blood pressure of -1.0mmHg (-2.2 to 0.1mmHg). Much stronger effects were observed among men who were born at term and were in the top third of body mass index at age 50, for whom a 1000g increase in birth weight was associated with a change of -9.1mmHg (-16.4 to-1.9mmHg) systolic and -4.2mmHg (-8.3 to -0.1mmHg) diastolic blood pressure. Men who were light at birth (<3250g) but were above median adult height had particularly high blood pressure. Adjustment for insulin concentrations reduced the associations of birth weight with systolic and diastolic blood pressure. CONCLUSIONS: A failure to realise growth potential in utero (as indicated by being light at birth but tall as an adult) is associated with raised adult blood pressure. Impaired fetal growth may lead to substantial increases in adult blood pressure among only those who become obese. Metabolic disturbances, possibly related to insulin resistance, may provide a pathway through which fetal growth affects blood pressure.

Birth Weight↗
PubMed1996

Relation of size at birth to non-insulin dependent diabetes and insulin concentrations in men aged 50-60 years.

OBJECTIVE: To establish whether the relation between size at birth and non-insulin dependent diabetes is mediated through impaired beta cell function or insulin resistance. DESIGN: Cohort study. SETTING: Uppsala, Sweden. SUBJECTS: 1333 men whose birth records were traced from a cohort of 2322 men born during 1920-4 and resident in Uppsala in 1970. MAIN OUTCOME MEASURES: Intravenous glucose tolerance test at age 50 years and non-insulin dependent diabetes at age 60 years. RESULTS: There was a weak inverse correlation (r=-0.07, P=0.03) between ponderal index at birth and 60 minute insulin concentrations in the intravenous glucose tolerance test at age 50 years. This association was stronger (r=-0.19, P=0.001) in the highest third of the distribution of body mass index than in the other two thirds (P=0.01 for the interaction between ponderal index and the body mass index). Prevalence of diabetes at age 60 years was 8% in men whose birth weight was less than 3250 g compared with 5% in men with birth weight 3250 g or more (P=0.08; 95% confidence interval for difference -0.3% to 6.8%). There was a stronger association between diabetes and ponderal index: prevalence of diabetes was 12% in the lowest fifth of ponderal index compared with 4% in the other four fifths (P=0.001; 3.0% to 12.6%). CONCLUSION: These results confirm that reduced fetal growth is associated with increased risk of diabetes and suggest a specific association with thinness at birth. This relation seems to be mediated through insulin resistance rather than through impaired beta cell function and to depend on an interaction with obesity in adult life.

B-Lymphocytes↗
PubMed1996

Self-perceived health status and inequalities in use of health services in Spain.

BACKGROUND: Socioeconomic differences have been described among the Spanish population. The purpose of this study was to investigate whether these variations are associated with differences in the use of health services between socioeconomic groups in Spain, taking into account self-perceived health as a measure of need. METHODS: Data were obtained from the 1987 Spanish National Health Survey. Socioeconomic position was measured by educational level and household income. Health care use was measured in two ways: prevalence of having consulted a doctor and of hospitalization over a defined period of time. Logistic regression models were used to analyse the relationship of interest. RESULTS: After adjustment for age, an inverse association was seen between education and both consultation with a doctor and hospitalization. A very different picture emerged when the association between socioeconomic position and probability of health service use was examined according to level of self-perceived health. Among those with poor or very poor health, people in higher educational groups showed the greatest probability of consulting a doctor (odds ratio [OR] = 1.41, 95% confidence interval [CI] : 0.89-2.23) or of being hospitalized (OR = 1.79, 95% CI : 1.09-2.93) compared to those in the lower educational groups. The corresponding OR for household income were 1.02 (95% CI : 0.74-1.42) for consultation with a doctor and 1.67 (95% CI : 1.15-2.44) for hospitalization. These finding were broadly similar for men and women. CONCLUSIONS: There is a socioeconomic variation in the pattern of use of health services in Spain in the sense that among those with poor self-perceived health, the more privileged have higher levels of health services use than others.

Adolescent↗
PubMed1996

Isolation, car ownership, and small area variation in incidence of acute lymphoblastic leukaemia in children.

To determine whether increased rates of childhood acute lymphoblastic leukaemia (ALL) which had been reported in isolated areas could be attributed to higher proportions of households owning cars, ecological analysis was performed with electoral wards as area units. Previous data were re-analysed using the proportion of households having no car, taken from the 1981 census of England and Wales, as an additional explanatory factor. A specialist registry of haematopoietic malignancies covering one-third of England and Wales (3270 electoral wards) recorded 438 cases of ALL in children diagnosed 1984-89, including 304 in the childhood peak (at ages 1-7 years). Relative risks were derived by Poisson regression of total childhood ALL and at ages 1-7 years for groups of electoral wards classified by isolation and car ownership. Multivariable analyses included adjustment for socio-economic status. No evidence of increased risk of childhood ALL in areas where more households own cars was found. ALL at ages 1-7 years was inversely associated with car ownership (risk in wards with least cars relative to those with most cars = 2.28, 95% CI: 1.12-4.64). The associations with geographic isolation persisted after allowing for car ownership (risks for ALL in young children in isolated relative to built-up areas = 2.19, 95% CI: 1.44-3.33). Levels of car ownership cannot explain the increased rates of childhood ALL which have been observed in isolated areas. No support has been found for a hypothesis relating these excesses to benzene exposure of children transported in cars. The previous explanation for the small area variation of childhood ALL in terms of geographical isolation and interpretation in terms of exposure to common infections continues to be justified.

Adolescent↗
PubMed1995

Mortality from cardiovascular disease among interregional migrants in England and Wales.

OBJECTIVE: To investigate the extent to which geographical variations in mortality from ischaemic heart disease and stroke in Britain are influenced by factors in early life or in adulthood. DESIGN: Longitudinal study of migrants. SUBJECTS: 1% sample of residents in England and Wales born before October 1939 and enumerated at the 1971 census (the Office of Population Censuses and Surveys' longitudinal study). MAIN OUTCOME MEASURE: 18,221 deaths from ischaemic heart disease and 9899 deaths from stroke during 1971-88 were analysed by areas of residence in 1939 and 1971. These included 2928 deaths from ischaemic heart disease and 1608 deaths from stroke among individuals moving between 14 areas defined by the major conurbations and nine standard administrative regions of England and Wales. RESULTS: The southeast to northwest gradient in mortality from ischaemic heart disease was related significantly to both the 1939 area (chi 2 = 6.09, df = 1) and area in 1971 (chi 2 = 5.05, df = 1). Geographical variations in mortality from stroke were related significantly to the 1939 area (chi 2 = 4.09, df = 1) but the effect of area in 1971 was greater (chi 2 = 8.07, df = 1). The effect of 1971 area on mortality from stroke was largely due to a lower risk of death from stroke among individuals moving into Greater London compared with migrants to the rest of the South East region (chi 2 = 4.54, df = 1). CONCLUSIONS: Geographical variations in mortality from cardiovascular disease in Britain may be partly determined by genetic factors, environmental exposures, or lifestyle acquired early in life, but the risk of fatal ischaemic heart disease and stroke changes on migration between areas with differing mortality. The low risk of death from stroke associated with residence in Greater London is acquired by individuals who move there.

Adult↗
PubMed1995

Breast cancer in Swedish women before age 50: evidence of a dual effect of completed pregnancy.

We set out to detect a transient increase in risk of breast cancer following childbirth, the existence of which has been postulated, but for which empirical evidence is contradictory. Breast cancers and births occurring among the cohort of Swedish women born after 1939 were linked, yielding 3,439 cases and 25,140 age-matched controls with at least two children. Within three years of their last childbirth, women had an estimated rate of breast cancer of 1.21 (95 percent confidence interval [CI] = 1.02-1.44) times that of women whose last birth was 10 or more years earlier, after adjustment for parity and age at first birth. Further analyses suggested that this effect reflected, in part, a small transient increase in breast cancer risk that lasts for about three years following completed pregnancy. The effect of age at first birth on breast cancer risk appears to be confounded by time since last birth; the parity-adjusted rate ratio for having a first birth at age 35 years or more compared with under 20 years is reduced from 1.72 (CI = 1.14-2.58) to 1.36 (CI = 0.88-2.09) on additional adjustment for time since last birth. A transient increase in breast cancer risk after childbirth appears thus appears to account for part of the effect of age at first birth on breast cancer risk.

Adult↗
PubMed1995

Adult height and mortality in London: early life, socioeconomic confounding, or shrinkage?

STUDY OBJECTIVE: To examine in detail the cause specific associations between height and mortality. DESIGN: A prospective cohort study with an 18 year mortality follow up. SETTING AND PARTICIPANTS: The Whitehall study of 18,403 men in the civil service in London examined between 1967 and 1969 aged 40-64 and followed up for mortality until the end of January 1987. MAIN RESULTS: There was considerable variation in the strength of height-mortality association by cause. Respiratory disease showed the strongest inverse association, cardiovascular disease a moderate effect, and all neoplasms virtually no effect. Adjustment for age and civil service grade reduced the strength of these associations slightly, but had no impact on the heterogeneous pattern by cause (chi 2 3df p < 0.001). The height-mortality association declined with the length of follow up. By 15+ years, the only appreciable height affect was for respiratory disease mortality. CONCLUSIONS: The attenuation of the height-mortality association with length of follow up might be explained by differential height reduction before entry that was greatest for people who were already ill, and hence at greatest risk of dying. The cause specific variation in the height-mortality association lends little support to the contention that impaired growth in childhood is a marker of general susceptibility to disease in adulthood.

Adult↗
PubMed1994

Mortality in the British printing industry: a historical cohort study of trade union members in Manchester.

A historical cohort study of the printing industry was established after an anecdotal report of a cluster of cases of bladder cancer in a newspaper factory in Manchester. The cohort comprised some 9500 men who were members of one or other of two trade unions (the NGA and NATSOPA) in the Manchester area between 1949 and 1963. During the follow up period (1949-83) 3482 deaths occurred among men born in 1890 or later; follow up was 97% complete. The results of the study do not support the hypothesis of an occupational risk of bladder cancer in the printing industry. The NGA have a standardised mortality ratio (SMR) of 63 (95% confidence interval (95% CI) 31-113) and NATSOPA an SMR of 113 (95% CI 67-178) based on 11 and 18 deaths from bladder cancer, respectively. Men involved in newspaper letterpress printing have a high mortality from lung cancer (SMR = 179, 95% CI 144-218) that is consistent with the findings of previous studies. Increased mortality from cancer of the buccal cavity and pharynx was found for NATSOPA workers in the newspaper industry; editorial workers had an SMR of 1053 (95% CI 128-3803) and clerical workers had an SMR of 638 (95% CI 132-1864). This is consistent with a review of published studies, which strongly suggest that workers in the printing industry have an increased risk of mortality from cancers of the buccal cavity and pharynx. Socioeconomic differences in union composition, rather than occupational factors, may account for the lower mortality in the NGA compared with NATSOPA. The NGA, a craft union, had an all causes SMR of 92 (95% CI 88-97), whereas NATSOPA covered a broader span of occupations and skill levels, and had an all causes SMR of 112 (95% CI 106-117); the NATSOPA and NGA all causes rate ratio was 1.21 (95% CI 1.13-1,29).

Adult↗
PubMed1994

Lung cancer among newspaper printers exposed to ink mist: a study of trade union members in Manchester, England.

A nested case-control study of lung cancer among men exposed to ink mist in newspaper production with rotary letterpress technology is presented. It is based within a historical cohort of 9232 printing workers in Manchester (1949-63). Men who operated newspaper rotary letterpress machines had a lung cancer standardised mortality ratio (SMR) of 179 (95% confidence interval (95% CI) 144-218) when compared with rates for England and Wales for the follow up period 1950-83. When adjustment was made for the higher rates in the local area, the SMR was reduced to 122 (95% CI 98-148). The nested case control study was based on 110 lung cancer cases (1949-86) and 316 matched controls. Duration of work in a rotary letterpress machine room was positively associated with risk of lung cancer (chi 2 linear trend = 3.30, p = 0.07); mean with 30 or more years duration of exposure had a risk of 1.73 (95% CI 0.94-3.17), relative to those with less than 20 years of exposure. Adjustment for period of first exposure in a machine room reduced the strength of the positive duration effect. The magnitude of the SMRs found in the cohort study could be explained by confounding with smoking. The duration effect seen in the case-control study, however, suggests that there may be a real effect of exposure to letterpress ink mists. This is biologically plausible, as benzo[a]pyrene, a known human carcinogen, has been found in appreciable concentrations in the atmosphere of rotary letterpress machine rooms.

Adult↗
PubMed1994

Socioeconomic factors and height of preschool children in the Czech Republic.

The effect of socioeconomic factors on growth was investigated among 2275 children 3 to 6 years old attending nurseries in the Czech Republic. Measured heights of children were converted into height-for-age z scores. After adjustment for birthweight, parental height, and other socioeconomic variables, only mother's education was independently and significantly associated with children's height; adjusted differences in z scores between children of secondary- and university-educated mothers and children of mothers with only primary education were 0.12 and 0.31, respectively. This is equivalent to 0.5 and 1.5 cm, respectively, for children 5 years old.

Body Height↗
PubMed1993

Socioeconomic characteristics of interregional migrants in England and Wales, 1939-71.

"Data from the Longitudinal Study (LS) of the Office of Population Censuses and Surveys are used to examine patterns of regional migration in England and Wales between 1939 and 1971. The source of information on region in 1939 is from a national population register established shortly after the start of the Second World War." The results suggest that "overall, 18% of persons in the analysis moved between regions from 1939 to 1971. Migrants tended to be socioeconomically advantaged compared with nonmigrants. Moreover, those moving to regions where the nonmigrants were the most advantaged, were themselves the most advantaged of the migrants. This paper illustrates a new source of data on long-term migration that deserves further exploration."

Demography↗
PubMed1992

Air pollution and infant mortality in the Czech Republic, 1986-88.

An ecological study of infant mortality and air pollution was conducted in the Czech Republic. Routinely collected data on infant mortality and air pollution in the period 1986-88 were analysed for the 46 of the 85 districts in the republic for which both were available. The independent effects of total suspended particulates (TSP-10), sulphur dioxide (SO2), and oxides of nitrogen (NOx) adjusted for district socioeconomic characteristics, such as income, car ownership, and abortion rate, were estimated by logistic regression. We found weak positive associations between neonatal mortality and quintile of TSP-10 and SO2. Stronger adjusted effects were seen for postneonatal mortality, with a consistent increase in risk from the lowest to the highest TSP-10 quintile (p < 0.001). Weaker and less consistent evidence of a positive association with NOx (p = 0.061) was observed. The strongest effects were seen for postneonatal respiratory mortality, which increased consistently from lowest to highest TSP-10 quintile (p = 0.013). There was also a suggestion of a positive association with SO2 (p = 0.062). The highest to lowest quintile risk ratios for postneonatal respiratory mortality were 2.41 (95% Cl 1.10-5.28) for TSP-10, 3.91 (0.90-16.9) for SO2, and 1.20 (0.37-3.91) NOx. The specificity of the association between air pollution quintile (especially TSP-10) and postneonatal respiratory mortality is consistent with the known effects of air pollution on respiratory disease morbidity in children. These ecological associations require confirmation in an individually based study.

Abortion, Legal↗
PubMed1992

Social class differences in infant mortality in Sweden: comparison with England and Wales.

OBJECTIVES: To investigate social class differences in infant mortality in Sweden in the mid-1980s and to compare their magnitude with that of those found in England and Wales. DESIGN: Analysis of risk of infant death by social class in aggregated routine data for the mid-1980s, which included the linkage of Swedish births to the 1985 census. SETTING: Sweden and England and Wales. SUBJECTS: All live births in Sweden (1985-6) and England and Wales (1983-5) and corresponding infant deaths were analysed. The Swedish data were coded to the British registrar general's social class schema. MAIN OUTCOME MEASURES: Risk of death in the neonatal and postneonatal period. RESULTS: Taking the non-manual classes as the reference group, in the neonatal period in Sweden the manual social classes had a relative risk for mortality of 1.20 (95% confidence interval 1.02 to 1.43) and those not classified into a social class a relative risk of 1.08 (0.88 to 1.33). In the postneonatal period the equivalent relative risks were 1.38 (1.08 to 1.77) for manual classes and 2.14 (1.65 to 2.79) for the residual; these are similar to those for England and Wales (1.43 (1.36 to 1.51) for manual classes, 2.62 (2.45 to 2.81) for the residual). CONCLUSIONS: The existence of an equitable health care system and a strong social welfare policy in Sweden has not eliminated inequalities in post-neonatal mortality. Furthermore, the very low risk of infant death in the Swedish non-manual group (4.8/1000 live births) represents a target towards which public health interventions should aim. If this rate prevailed in England and Wales, 63% of postneonatal deaths would be avoided.

England↗
PubMed1991

Influence of birth weight on differences in infant mortality by social class and legitimacy.

OBJECTIVE: To investigate the influence of birth weight on the pronounced social class differences in infant mortality in Britain. DESIGN: Analysis of routine data on births and infant deaths. SETTING: England and Wales. SUBJECTS: All live births and infant deaths, 1983-5. MAIN OUTCOME MEASURE: Mortality in infants by social class, birth weight, and legitimacy according to birth and death certificates. RESULTS: Neonatal and postneonatal mortality (deaths/1000 births) increased with social class. Neonatal and postneonatal mortality was 4.2/1000 and 2.3/1000 respectively for social class I and 6.8/1000 and 5.6/1000 respectively for social class V. Mortality was lower among births registered within marriage (postneonatal 3.5/1000; neonatal 5.2/1000) than among those jointly registered outside marriage (5.1/1000; 6.4/1000); mortality was highest in those solely registered outside marriage (7.2/1000; 7.0/1000). For neonatal mortality the effect of social class varied with birth weight. Social class had little effect on neonatal mortality in low birthweight babies and increasing effect in heavier babies. For postneonatal mortality the effect of social class was similar for all birth weights and was almost as steep as for all birth weights combined. CONCLUSION: Birth weight mediates little of the effect of social class on postneonatal mortality.

Birth Weight↗
PubMed1989

A prospective study of the independent effects of parity and age at first birth on breast cancer incidence in England and Wales.

The independent effects of parity and age at first birth on breast cancer incidence are investigated in a 1% sample of women aged 16 to 59 from the 1971 Census of England and Wales. Over the period 1971-81, 1,003 breast cancer cases occurred in the cohort of 113,263 women who were either married, widowed or divorced at the time of Census. Age at first birth was positively related to breast cancer risk, women giving birth to their first child after 35 years being at greater risk than nulliparous women. This effect remained, after adjustment for number of live-born children. Breast cancer risk showed a statistically significant decline with increasing parity even after adjustment for age at first birth. These results are consistent with other published evidence which suggests that other births subsequent to the first have an independent effect on breast cancer risk.

Breast Neoplasms↗