Search PubMed⌕ Search

Biomedical subjects

F D Martinez

Publications and source records attributed to F D Martinez.

At least 109 records · Page 6Linked to original sources
PubMed1992

Enhanced allergic sensitisation related to parental smoking.

The objective of this study was to assess the role of parental smoking in changes, after a four year interval (1983-7), in the prevalence and severity of the atopic state in 166 pre-adolescent children. Allergy skin prick tests were related to parental smoking habits and their changes during this same interval. The total number of cigarettes smoked by parents decreased in 56 families while it increased in only 16. Boys had significantly more persistently positive skin tests and changed more frequently from negative to positive. The skin test index did not show significant changes in girls. This index did not change in children of persistent non-smokers or those starting to smoke during this period, while it increased among sons of those that quit smoking and of persistent smokers. This was not only due to those boys who became skin test positive during follow up. When analysis was restricted to 14 boys who had been skin test positive in 1983 and whose parents were persistent smokers, the index increased in eight, remained unchanged in four, and decreased in only two. This report supports the hypothesis that parental smoking is a factor that, together with specific allergenic exposure, may enhance allergic sensitisation in children.

Child↗
PubMed1992

Lymphocyte subpopulation number and function in infancy.

Normal values for percentages of lymphocyte subpopulations and functional responses to mitogen stimulation in infancy are not well established. In the present study, lymphocyte subpopulations were examined in umbilical cord blood samples and in peripheral blood samples drawn before 7 and 24 months of age (mean age 10.4 months) from a healthy population of infants born in Tucson, Arizona. Results indicate significant increases occurred from birth to later infancy in the percentages of total T cells (CD3), T-cell subsets (CD4, CD8) and B cells (CD20). The CD4/CD8 ratio and the functional responses to ConA and PWM mitogens significantly decreased from birth to later infancy. PHA responsiveness did not show a significant change. Results from cross-sectional analyses (n = 271) were supported in a smaller longitudinal subset (n = 37). There were no detectable ethnic- or gender-related differences in cord blood or samples obtained in later infancy. The normal values established in this study will be useful in studies of immune-system maturation and in the clinical evaluation of newborns, infants, and toddlers suspected of either acquired or congenital immune-deficiency states.

Cell Count↗
PubMed1992

Longitudinal effects of passive smoking on pulmonary function in New Zealand children.

In this study we examined the longitudinal effects of smoke exposure on lung function in a cohort of New Zealand children observed from 9 to 15 yr of age. Possible exposures included in utero exposure from mothers smoking during pregnancy, passive smoke from parents, and active smoking by the children. Lung function measures of forced expiratory volume in one second (FEV1) and vital capacity (VC) were measured biennially and ratios (FEV1/VC) were computed. The data were analyzed using longitudinal methodology, and all subjects with at least one pulmonary function test and responses to the questions concerning smoke exposures were included (n = 634). Subjects reporting wheeze or asthma were examined as a separate subgroup. In the whole cohort, no significant detrimental effects were detected for absolute FEV1 or VC in either sex, related to active or passive smoke exposures. Parental smoking was, however, associated with persistent but mild and nonprogressive impairment of the FEV1/VC ratio in males, an effect that was present at the time lung function measurements were first made. This effect was not seen in females. In children with reported wheeze or asthma, parental smoking had progressive, more serious, and clinically significant effects on the FEV1/VC ratio among adolescents of both sexes, causing a mean reduction in FEV1/VC ratios by age 15 of 3.9% in males and 2.3% in females, in contrast to the observed increase in FEV1/VC ratios with age seen in nonexposed wheezing children. We conclude that passive smoking is a major contributing factor to the development and persistence of airflow limitation in wheezing children.

Adolescent↗
PubMed1992

The predictive relationship between serum IgE levels at birth and subsequent incidences of lower respiratory illnesses and eczema in infants.

Cord serum IgE levels are predictive of subsequent atopic diseases early in life. Lower respiratory illnesses (LRI) have often been included with atopic diseases in infancy but have not been examined as a separate entity for a relation to cord IgE levels. Among 767 healthy newborns in Tucson, Arizona studied longitudinally, cord serum IgE levels were directly related to the subsequent incidence of eczema. In contrast, the incidence of LRI not only failed to show a direct relationship to IgE levels but actually decreased with increasing cord IgE levels from 34.8% in the lowest cord IgE group to 22.2% in the highest IgE group (greater than 1.0 IU/ml IgE; p for trend chi-square less than 0.03). Limiting LRI to those with wheeze did not alter the inverse relationship with IgE levels. The inverse LRI-IgE relationship was strong for non-RSV LRI, whereas RSV LRI had neither a direct nor an inverse relationship. These inverse LRI-IgE relationships were significant for LRI occurring in infants before but not after 6 months of age. Maternal (but not paternal) allergic history was associated with higher cord IgE levels and with an increased incidence of LRI, the latter effect being independent of IgE. This study suggests that most LRI in the first year of life are not early manifestations of an allergic predisposition.

Arizona↗
PubMed1992

Increased incidence of asthma in children of smoking mothers.

The relationship between parental smoking and both subsequent development of asthma and subsequent lung function (before age 12) was studied in more than 700 children enrolled before age 5. Children of mothers with 12 or fewer years of education and who smoked 10 or more cigarettes per day were 2.5 times more likely (95% confidence interval 1.42 to 4.59; P = .0018) to develop asthma and had 15.7% lower maximal midexpiratory flow (P less than .001) than children of mothers with the same education level who did not smoke or smoked fewer than 10 cigarettes per day. These relationships were independent of self-reported respiratory symptoms in parents. There was no association between maternal smoking and subsequent incidence of asthma or maximal midexpiratory flow among children of mothers with more than 12 years of education. It is concluded that children of lower socioeconomic status may be at considerable risk of developing asthma if their mothers smoke 10 or more cigarettes per day. It is speculated that recently reported increases in prevalence of childhood asthma may be in part related to the increased prevalence of smoking among less educated women.

Asthma↗
PubMed1991

Risk factors for respiratory syncytial virus-associated lower respiratory illnesses in the first year of life.

The relation of breast feeding and other factors to the incidence of respiratory syncytial virus-associated lower respiratory tract illness (RSV-LRI) in the first year of life is examined. The study population is 1,179 healthy infants enrolled at birth between May 1980 and January 1984 into the Tucson Children's Respiratory Study, Tucson, Arizona. Each subject's data were assessed at each month of age during the first year of life, during those months when respiratory syncytial virus was isolated. A number of significant relations were observed, particularly between 1 and 3 months of age. At this age, the risk of having a RSV-LRI increased in association with less than 1-month or no breast feeding, with being male, and with increasing numbers of others sharing the child's bedroom. In multivariate analysis, only sex and the number of others sharing the room remained as significant direct effects. However, a significant interaction demonstrated that breast feeding has a protective role in relation to RSV-LRIs for those infants of mothers with a lower education level. The risk of having a RSV-LRI increases with combinations of risk factors. Being in day care was a significant risk factor in the 7- to 9-month age range. The RSV-LRI rate also varies by birth month. A separate case-control study assessed relations of RSV-LRIs with cord serum RSV antibody. Those with lower cord serum RSV antibody, who also have minimal breast feeding, were found to be especially at risk for RSV-LRIs in the first 5 months of life.

Antibodies, Viral↗
PubMed1991

Relationship of parental smoking to wheezing and nonwheezing lower respiratory tract illnesses in infancy. Group Health Medical Associates.

The relationship between parental smoking and lower respiratory tract illness (LRI) was studied in a large cohort of infants followed prospectively from birth. Illnesses were diagnosed by physicians using agreed-on criteria, and parental smoking histories were obtained by questionnaire. The LRIs were differentiated into wheezing and nonwheezing episodes, and the age at first illness of either type was evaluated in relation to smoking by parents. The odds of having an LRI were significantly higher in children whose mothers smoked (odds ratio 1.52; confidence interval 1.07 to 2.15). The odds were higher if the mother smoked a pack of cigarettes or more per day and if the child stayed home rather than attending day care (odds ratio 2.8; confidence interval 1.43 to 5.5). Logistic regression indicated that the LRI rate was significantly elevated both in children exposed to heavy maternal smoke in the absence of day care, and in those who use day care but were not exposed to maternal smoking of a pack or more per day. These findings could not be attributed to other confounding variables. Neither paternal smoking nor smoking by other household members was consistently related to the LRI rate. The relationship of maternal smoking to LRI rate was evident for both wheezing and nonwheezing illnesses. Maternal smoking of a pack or more per day was also related to an early age at first LRI, for both wheezing (p less than 0.05) and nonwheezing (p less than 0.002) illnesses. In sum, maternal smoking is associated with a higher rate of LRIs in the first year, particularly when mothers smoked a pack or more per day and when the child did not use day care.

Bronchial Diseases↗
PubMed1991

Relationship of total serum IgE levels in cord and 9-month sera of infants.

To characterize IgE levels at birth and changes in those levels during the first year of life and to identify factors that might influence IgE levels in infancy, we measured IgE levels in 1074 umbilical cord sera and in 697 sera obtained at 9 months of age in a healthy population of infants enrolled at birth into the Children's Respiratory Study in Tucson, Arizona, U.S.A. Serum IgE levels at birth and 9 months were log normally distributed with geometric means of 0.09 and 3.87 IU/ml, respectively. Cord serum IgE levels were unaffected by maternal smoking. Levels varied according to month of birth with a nadir in September. Cord and 9-month serum IgE levels were higher in boys than in girls, Hispanics compared with Anglos, and infants who developed eczema compared with those who did not, but the mean increases in log IgE from birth to 9 months were not significantly affected by these factors. A significant correlation between IgE levels at cord and 9 months was observed (r = 0.44; P less than 0.0001). Also, mean log IgE levels at 9 months in infants grouped according to cord serum IgE levels maintained the same rank order of mean values as the cord groups. These data indicate that 9-month IgE levels are influenced by cord serum IgE levels and that the main influence of gender, ethnicity and susceptibility to eczema on IgE levels occurs before birth.

Age Factors↗
PubMed1991

Initial airway function is a risk factor for recurrent wheezing respiratory illnesses during the first three years of life. Group Health Medical Associates.

We recently reported a significant relationship between lung function measured prior to any lower respiratory tract illness and subsequent wheezing illnesses during the first year of life (N Engl J Med 1988; 319:1112-7). Follow-up has continued for this group of infants during the second and third years of life. When compared with never wheezers, infants who wheezed during the first year of life and had at least one additional lower respiratory illness had 22% lower initial levels of an indirect index of airway conductance derived from the shape of tidal breathing curves (p less than or equal to 0.01), 22% lower respiratory conductance (p less than or equal to 0.05), 25% lower maximal flows at the end-expiratory point (p less than or equal to 0.01), and 10% lower functional residual capacity (p less than or equal to 0.05). Infants who wheezed only once during the first 3 yr of life or who started wheezing during the second year of life had normal tidal breathing curves but significantly lower maximal expiratory flows (p less than or equal to 0.05). Their functional residual capacity was also lower than that of never wheezers (p less than or equal to 0.05). We conclude that diminished initial airway function may be a predisposing factor for recurrent wheezing respiratory illnesses starting in the first year of life. Infants who will have only one wheezing respiratory illness or who will start wheezing after the first year of life seem to have lower levels for some but not for all lung function tests performed in this study.

Age Factors↗
PubMed1991

Sudden infant death syndrome and small airway occlusion: facts and a hypothesis.

Respiratory failure is almost certainly the cause of death in the majority of cases of sudden infant death syndrome (SIDS), but the mechanisms leading to it have not been elucidated. SIDS shares many environmental and socioeconomic risk factors with severe forms of bronchiolitis, and the age distribution of incident cases is similar. Present knowledge of lung and airway development during infancy, determinants of peripheral airway patency, changes in lung surface activity in infants with SIDS, and fluid film dynamics in small airways are reviewed. It is hypothesized that many cases of SIDS may be due to a final episode of progressive peripheral bronchial occlusion in infants with preceding critically diminished conductance of the smaller airways.

Airway Obstruction↗
PubMed1990

Infants with upper respiratory illnesses have significant reductions in maximal expiratory flow.

We studied maximal expiratory flows at functional residual capacity (VmaxFRC) obtained by use of the chest compression technique in 9 infants who had signs of upper respiratory illness (URI) at the time of testing, and in 9 infants who were symptom-free but whose parents reported they had a URI in the previous month. When compared to 109 infants with no URI, infants with current URI had 40% lower VmaxFRC (mean +/- SD: 125.7 +/- 54.5 mL/s vs. 73.6 +/- 53.6 mL/s; P less than 0.01). Infants with a past URI had mean values for VmaxFRC (120.2 +/- 50.2 mL/s) that were not significantly different from those of infants with no URI. Changes in the shape of the flow-volume loop analogous to those reported in infants with lower airway obstruction were also noticed in infants with current URI. These findings suggest that, as in older children and adults, clinically unapparent alterations in lower airway function occur during URI in infants.

Analysis of Variance↗
PubMed1990

A longitudinal study of risk factors in asthma and chronic bronchitis in childhood.

The prevalence, persistence, incidence and remission rates of reported diagnosed asthma and chronic bronchitis has been studied longitudinally over ten years in a representative community sample of children and adolescents. The objectives are to evaluate the rates of change over time, the role of family history of disease, and the social risk factors in the longitudinal course of disease. The relationship between the two reported diagnoses is very high, about half of each group having the other diagnosis. Each diagnosis has specific symptoms with which it is associated. Remission of clinical disease is associated with continuing symptoms in about half of such cases. The incidence rates and remissions of cases as they have occurred over time were associated with different symptoms and risk factors. A family history of lung disease and family social characteristics are significant risk factors affecting the presence of these diseases, and how they change. Discussion suggests these factors may affect possible precursors, such as lower respiratory tract illnesses, as well as personal habits (such as smoking), which are related to both diagnoses. Further, the interactions of these risk factors appear to significantly influence impairments of lung function at the beginning of adult life, and potential subsequent disease.

Adolescent↗
PubMed1990

Passive smoking in childhood--tobacco smoke.

Prevalence of cigarette smoking varies widely in different countries, ranging, at the age of 13, from 2% to 5% (Sweden, United States) to more than 30% (Australia, Uruguay). Even if the prevalence of smokers among male adolescents is decreasing in western countries, it is increasing among girls and, in developing countries, male adolescent smokers still reach 40% (and up to 70%-80%). The determination of saliva cotinine levels, a product of nicotine metabolism, is an useful indicator of exposure to passive or active smoking. In a study of 210 children aged 9-13 years, we found detectable levels of saliva cotinine in 13% of children who lived in nonsmoking families and denied being regular smokers and in only 60% of children living in families with heavy cigarette consumption. This wide variations of a marker of smoking exposure may explain the differences in reported consequences of tobacco smoke in investigations conducted in different places and on different target populations. We later studied the effects of environmental tobacco smoke (ETS) in a sample of 166 nine-year-old children. The relationship between parental smoking and degree of bronchial responsiveness in males was significant. Also, prick skin test reactivity to allergens was significantly increased in children of smoking parents. Many studies concerning the effects of ETS exposure seem to demonstrate that not only the lungs and not only children are affected even if the difficulty of the epidemiology in such a field must suggest caution in interpreting the results.(ABSTRACT TRUNCATED AT 250 WORDS)

Asthma↗
PubMed1990

Increased serum IgE and increased prevalence of eosinophilia in 9-year-old children of smoking parents.

We studied the relationship of serum IgE levels and eosinophil counts with passive smoking in 9-year-old, nonselected children from three Italian towns near Rome. Male children of smoking parents had a significantly higher total count and percentage of eosinophils (p = 0.008) and higher IgE levels (p = 0.01) than male children of nonsmoking parents. Prevalence of eosinophilia (defined as greater than or equal to 4% of total white blood cell count) was significantly correlated with the number of cigarettes smoked by parents among boys (p = 0.003) but not among girls (p = 0.20). There was a significant trend (p = 0.008) for prevalence of eosinophilia to increase with increasing levels of serum IgE. For any given level of serum IgE, the frequency of eosinophilia was higher among children of smoking parents than among children of nonsmoking parents. When parental smoking was studied in a multivariable analysis and after controlling for the other variable, it was still significantly associated with eosinophilia in the children of these smoking parents but not with serum IgE levels. We conclude that parental smoking is associated with a significant enhancement of the expression of the most important markers of allergic sensitization in the children of smoking parents. This is particularly evident for boys and may explain, at least in part, the increased frequency of respiratory symptoms in children of smoking parents.

Child↗
PubMed1989

Breast feeding and lower respiratory tract illness in the first year of life. Group Health Medical Associates.

OBJECTIVE: To assess the relation between breast feeding and subsequent experience of lower respiratory tract illness. DESIGN: Prospective (from well child visits) and retrospective (from maternal recall) study of breast feeding and prospective assessment by paediatricians of lower respiratory tract illness in infants during first year of life. SETTING: Health maintenance organisation. PARTICIPANTS: Over 1000 infants who were healthy at birth and whose parents used the paediatricians of a local health maintenance organisation. MAIN OUTCOME MEASURES: Duration of breast feeding and type of lower respiratory tract illness (wheezing and non-wheezing) at different age intervals during the first year of life. RESULTS: Breast feeding was associated with a decreased incidence of wheezing illnesses only in the first four months of life. Interactions existed between breast feeding and sharing a room, being Mexican American, and being a boy. Multivariate techniques showed that after controlling for a variety of factors children who received minimal breast milk had a greater risk of early wheezing illnesses; the risk was further increased by simultaneous exposure to sharing a room. CONCLUSION: Breast feeding seems to protect against wheezing respiratory tract illnesses in the first four months of life, particularly when other risk factors are present.

Breast Feeding↗
PubMed1989

Association of asthma with serum IgE levels and skin-test reactivity to allergens.

We investigated the association of self-reported asthma or allergic rhinitis with serum IgE levels and skin-test reactivity to allergens in 2657 subjects in a general-population study. Regardless of the subjects' status with respect to atopy or their age group, the prevalence of asthma was closely related to the serum IgE level standardized for age and sex (P less than 0.0001), and no asthma was present in the 177 subjects with the lowest IgE levels for their age and sex (greater than 1.46 SD below the mean). The log odds ratio increased linearly with the serum IgE level after we controlled for possible confounders and the degree of reactivity to skin tests. In contrast, allergic rhinitis appeared to be associated primarily with skin-test reactions to common aeroallergens, independently of the serum IgE level. We conclude that asthma is almost always associated with some type of IgE-related reaction and therefore has an allergic basis, although not all the allergic stimuli that cause asthma appear to have been included in the battery of common aeroallergens we used to assess atopic status. These findings challenge the concept that there are basic differences between so-called allergic ("extrinsic") and nonallergic ("intrinsic") forms of asthma.

Adolescent↗
PubMed1988

Diminished lung function as a predisposing factor for wheezing respiratory illness in infants.

In a prospective study of 124 infants enrolled as newborns, we assessed the relation between initial lung function and the subsequent incidence of lower respiratory tract illness during the first year of life. The risk of having a wheezing illness was 3.7 times higher (95 percent confidence interval, 0.9 to 15.5; P = 0.06) among infants whose values for total respiratory conductance (the reciprocal of the resistance to air flow of the entire respiratory system) were in the lowest third, as compared with infants with values in the upper two thirds of the range of values for the group. Boys with initial values in the lowest third for an indirect index of airway conductance had a 10-fold increase (95 percent confidence interval, 2.2 to 44.2; P = 0.001) in the risk of having a wheezing illness. A 16-fold increase (95 percent confidence interval, 1.7 to 147.1; P = 0.002) in the risk of having a wheezing illness was found among girls whose initial values for lung volume at the end of tidal expiration were in the lowest third. We conclude that diminished lung function is a predisposing factor for the development of a first wheezing illness in infants.

Airway Resistance↗