Reduced basal salivary cortisol in children with asthma and allergic rhinitis

Stress as a possible cause of a high incidence of hypertension and diabetes and a low incidence of asthma in the Iraqi population

Hypertension and diabetes represent a significant public health burden worldwide and are significant risk factors for heart disease and stroke. Nevertheless, Iraqi people, in particular, experience higher levels of stress due to political instability and economic issues. The study aimed to investigate the prevalence of common morbidities among Iraqi patients and the possible relationship with exposure to stress. The data was collected from patients (n=500) who attended the health center in Najaf, Iraq, between 25 August 2021 and 30 September 2021. The prevalence of hypertension, diabetes, and asthma among Iraqi people was determined along with patients' awareness and control of these conditions. In addition, patients were asked about their experiences with stress, including the type of stress they encountered. Our findings revealed that nearly 47% of patients involved in this study had hypertension, with the highest percentage in patients over 40. Moreover, the incidence of diabetes was 12%, with the highest incidence in the age group of 40-59. The incidence of asthma was lower in all groups. Data analysis concerning exposure to stress demonstrated that about 60% of patients suffer from a stressful life. We found that the incidence of hypertension and diabetes was high while the incidence of asthma was low. This study also reveals that a considerable number of people were unaware of their hypertension and diabetes. Exposure to daily life stress among Iraqi people may play a role in the observed incidence of these morbidities.

Metabolomic profiling reveals extensive adrenal suppression due to inhaled corticosteroid therapy in asthma

The application of large-scale metabolomic profiling provides new opportunities for realizing the potential of omics-based precision medicine for asthma. By leveraging data from over 14,000 individuals in four distinct cohorts, this study identifies and independently replicates 17 steroid metabolites whose levels were significantly reduced in individuals with prevalent asthma. Although steroid levels were reduced among all asthma cases regardless of medication use, the largest reductions were associated with inhaled corticosteroid (ICS) treatment, as confirmed in a 4-year low-dose ICS clinical trial. Effects of ICS treatment on steroid levels were dose dependent; however, significant reductions also occurred with low-dose ICS treatment. Using information from electronic medical records, we found that cortisol levels were substantially reduced throughout the entire 24-hour daily period in patients with asthma who were treated with ICS compared to those who were untreated and to patients without asthma. Moreover, patients with asthma who were treated with ICS showed significant increases in fatigue and anemia as compared to those without ICS treatment. Adrenal suppression in patients with asthma treated with ICS might, therefore, represent a larger public health problem than previously recognized. Regular cortisol monitoring of patients with asthma treated with ICS is needed to provide the optimal balance between minimizing adverse effects of adrenal suppression while capitalizing on the established benefits of ICS treatment.

Early Adverse Experiences and Repeated Wheezing From 6 to 30 Months of Age: Investigating the Roles of Hypothalamic-Pituitary-Adrenal Axis Functioning, Child Sex, and Caregiving Sensitivity

This study examined associations among early adversity, diurnal cortisol, child sex, and caregiver sensitivity at age 6 months in relation to wheezing in children (47% male) followed to 30 months. Analyses included 676 mother-child dyads, 393 of whom completed an observational caregiver sensitivity measure. Participants were primarily ethnic minorities (42.7% Black, 25.4% Hispanic); 22.1% of children had ≥ 1 wheezing episode. Higher adversity was associated with increased wheeze frequency and blunted diurnal cortisol slope. The indirect effect of adversity on wheezing through cortisol slope was significant for females, but not males. Higher caregiver sensitivity was protective against wheezing for males, but not females, with high cortisol. Findings suggest complex associations among adversity, cortisol, child sex, and caregiver sensitivity in predicting wheezing.

Inhaled corticosteroids as treatment for adolescent asthma: effects on adult anxiety-related outcomes in a murine model

RATIONALE

Allergic asthma, typically controlled with inhaled corticosteroids (ICS), is the leading chronic health condition for youth under 18 years of age. During this peri-adolescent period, significant brain maturation occurs. Prior studies indicate that both chronic inflammation and corticosteroid medications increase risk for developing an internalizing disorder like anxiety.

OBJECTIVES

To determine if chronic ICS treatments exacerbate or alleviate anxiety symptoms associated with developmental allergic asthma, we used a mouse model to isolate the influence of ICS (fluticasone propionate, FLU) vs. airway inflammation (induced with house dust mite extract, HDM).

METHODS

During development, male and female BALB/cJ mice were repeatedly exposed to HDM or saline plus one of four FLU doses (none/vehicle, low, moderate, or high). In adulthood, we assessed lung inflammation, circulating and excreted corticosteroids, anxiety-like behavior, and gene expression in stress and emotion regulation brain regions.

RESULTS

FLU treatment decreased body weight and anxiety-like behavior and increased fecal corticosterone metabolite concentrations and Crhr2 gene expression in ventral hippocampus. FLU effects were only observed in saline/non-HDM-exposed mice, and the FLU doses used did not significantly decrease HDM-induced airway inflammation. Females had greater serum and fecal corticosterone concentrations, less anxiety-like behavior, and lower Crhr1 gene expression in ventral hippocampus and prefrontal cortex than males.

CONCLUSIONS

These findings suggest that steroid medications for youth with allergic asthma may not exacerbate anxiety-related symptoms, and that they should be avoided in children/adolescents without a health condition. The results are informative to future work on the use of corticosteroid medications during childhood or adolescent development.

Virus, allergic sensitisation and cortisol in infant bronchiolitis and risk of early asthma

Background

Acute bronchiolitis during infancy and human rhinovirus (HRV) lower respiratory tract infections increases the risk of asthma in atopic children. We aimed to explore whether specific viruses, allergic sensitisation or cortisol levels during acute bronchiolitis in infancy increase the risk of early asthma, using recurrent wheeze as a proxy.

Methods

In 294 children with a mean (range) age of 4.2 (0–12) months enrolled during hospitalisation for acute infant bronchiolitis, we analysed virus in nasopharyngeal aspirates, serum specific immunoglobulin E against food and inhalant allergens, and salivary morning cortisol. These factors were assessed by regression analyses, adjusted for age, sex and parental atopy, for risk of recurrent wheeze, defined as a minimum of three parentally reported episodes of wheeze at the 2-year follow-up investigation.

Results

At 2 years, children with, compared to without, recurrent wheeze had similar rates of respiratory syncytial virus (RSV) (82.9% versus 81.8%) and HRV (34.9% versus 35.0%) at the acute bronchiolitis, respectively. During infancy, 6.9% of children with and 9.2% of children without recurrent wheeze at 2 years were sensitised to at least one allergen (p=0.5). Neither recurrent wheeze nor incidence rate ratios for the number of wheeze episodes at 2 years were significantly associated with specific viruses, high viral load of RSV or HRV, allergic sensitisation, or morning salivary cortisol level during acute bronchiolitis in infancy.

Conclusion

In children hospitalised with acute infant bronchiolitis, specific viruses, viral load, allergic sensitisation and salivary morning cortisol did not increase the risk of early asthma by 2 years of age.

In infants with acute bronchiolitis, specific viruses including human rhinovirus, viral load and/or allergic sensitisation did not increase the risk of asthma by 2 years of age.http://bit.ly/2tCE9Yd

Quality of life, salivary cortisol and atopic diseases in young children

Background

Children with atopic disease may have reduced health-related quality of life (QoL) and morning cortisol. Possible links between QoL, morning cortisol and atopic disease are unclear. We aimed to determine if QoL was associated with morning salivary cortisol at two years of age, and if asthma, atopic dermatitis and/or allergic sensitisation influenced this association. Secondarily, we aimed to determine if QoL at one year of age was associated with salivary cortisol one year later.

Methods and findings

The Bronchiolitis All SE-Norway study included infants during hospitalisation for acute bronchiolitis in infancy (bronchiolitis group) and population-based control infants (controls). The present study included all 358 subjects with available Infant Toddler Quality of Life Questionnaire (ITQOL) from parents, consisting of 13 domains and morning salivary cortisol at two years of age. Answers from the same 0–100 score questionnaire, with optimal score 100 nine months after enrolment, was also available for 289 of these children at about one year of age. Recurrent bronchial obstruction was used as an asthma proxy. Atopic dermatitis was defined by Hanifin and Rajka criteria and allergic sensitisation by a positive skin prick test. Due to different inclusion criteria, we tested possible interactions with affiliation groups. Associations between QoL and cortisol were analysed by multivariate analyses, stratified by bronchiolitis and control groups due to interaction from affiliation grouping on results. At two years of age, QoL decreased significantly with decreasing cortisol in 8/13 QoL domains in the bronchiolitis group, but only with General health in the controls. The associations in the bronchiolitis group showed 0.06–0.19 percentage points changes per nmol/L cortisol for each of the eight domains (p-values 0.0001–0.034). The associations remained significant but diminished by independently including recurrent bronchial obstruction and atopic dermatitis, but remained unchanged by allergic sensitisation. In the bronchiolitis group only, 7/13 age and gender adjusted QoL domains in one-year old children were lower with lower cortisol levels at two years of age (p = 0.0005–0.04).

Conclusions

At two years, most QoL domains decreased with lower salivary cortisol among children who had been hospitalised for acute bronchiolitis in infancy, but for one domain only among controls. Recurrent bronchial obstruction and to a lesser extent atopic dermatitis, weakened these associations that nevertheless remained significant. After bronchiolitis, lower QoL in one-year old children was associated with lower salivary cortisol at two years.

Assessment of hair cortisol as a potential biomarker for possible adrenal suppression due to inhaled corticosteroid use in children with asthma: A retrospective observational study

BACKGROUND

Inhaled corticosteroids (ICS) are the recommended long-term control therapy for asthma in children. However, concern exists regarding potential adrenal suppression with chronic ICS use. Our pilot study reported that hair cortisol in children was 50% lower during ICS therapy than prior to therapy, suggestive of adrenal suppression.

OBJECTIVE

To evaluate hair cortisol concentration (HCC) as a potential biomarker for possible adrenal suppression from ICS use in children with asthma.

METHODS

A retrospective observational study was performed at asthma clinics in Vancouver, Winnipeg, and Toronto, Canada. Children (n = 586) were recruited from July 2012 to December 2014 inclusive of those without asthma, with asthma not using ICS, and with asthma using ICS. The most recent three-month HCC was measured by enzyme immunoassay and compared among the groups. Quantile regression analysis was performed to identify factors potentially affecting HCC.

RESULTS

The median HCC was not significantly different among the children: No ICS (n = 47, 6.7 ng/g, interquartile range (IQR) 3.7-9.8 ng/g), ICS Treated (n = 360, 6.5 ng/g, IQR 3.8-14.3 ng/g), and Controls (n = 53, 5.8 ng/g, IQR 4.6-16.7 ng/g). 5.6% of the children using ICS had hair cortisol <2.0 ng/g compared to none in the control groups (P < .05, comparing ICS Treated (20/360) to all Controls combined (0/100)) and only half had been exposed to systemic corticosteroids. Age, sex, BMI, and intranasal corticosteroid use were significantly associated with HCC.

CONCLUSIONS

Results suggest HCC may be a potential biomarker for adrenal suppression as a population of children using ICS with HCC < 2.0 ng/g was identified compared to none in the control groups. Further research is needed to determine if those children have or are at risk of adrenal suppression or insufficiency.

"Allergic mood" - Depressive and anxiety symptoms in patients with seasonal allergic rhinitis (SAR) and their association to inflammatory, endocrine, and allergic markers

A growing number of studies show an association between seasonal allergic rhinitis (SAR) with depression and anxiety. The underlying mechanisms of a link between SAR and affect, however, are still unclear. The objective of the present study was to investigate depressive symptoms and anxiety in SAR patients and their association to inflammatory and endocrine parameters. SAR patients (n=41) and non-allergic, healthy controls (n=42) were assessed during (pollen season) and out of symptomatic periods (non-pollen season). Inflammatory cytokine profile (Interleukin [IL]-2, IL-4, IL-6, IL-8, IL-10, IL-17, IFN-γ, TNF-α), Immunoglobulin-E (IgE), hair cortisol concentrations (HCC), as well as sleep quality were measured. The present data show that during acute allergic inflammation SAR patients experienced a significant increase in Beck Depression Inventory (BDI-) II scores when (a) compared to the asymptomatic period and (b) when compared to the non-allergic controls, while no differences in anxiety were observed. Increased BDI-II scores in SAR patients were significantly associated with levels of IL-6 as well as IL-6/IL-10 and IFN-γ/IL-10 ratios and further, to an early age at manifestation of SAR and poor sleep quality. These findings support a close relationship between acute allergic processes and affective states, with inflammatory cytokines, sleep, and age of manifestation as potentially relevant mediators.

Morning Salivary Cortisol in Young Children: Reference Values and the Effects of Age, Sex, and Acute Bronchiolitis

OBJECTIVE

To identify morning salivary cortisol reference values in infancy and at 2 years of age and to investigate the influence of age, sex and acute bronchiolitis.

STUDY DESIGN

In this South-East Norwegian cohort study, 308 children hospitalized with moderate to severe acute bronchiolitis in infancy in 2010-2011 were compared with 223 healthy controls included in 2012 by measuring morning salivary cortisol levels at inclusion and at 2 years of age. Samples were collected shortly after awakening after 6 am. The influences of age, sex, and acute bronchiolitis were assessed by regression analysis.

RESULTS

In infancy, cortisol values were higher in acute bronchiolitis, with an age- and sex-adjusted weighted mean group difference of 13.9 nmol/L (95% CI 8.1-19.7; P < .0001). The median level in reference group was 23.7 nmol/L (95% CI 9.7-119.6). At 2 years of age, sex but not inclusion groups differed, with significantly higher values in girls. The weighted mean of all boys' cortisol levels was 32.4 nmol/L, (95% CI 30.5-34.3), and all girls' levels were 36.9 nmol/L (95% CI 34.7-39.2; P < .003).

CONCLUSIONS

Salivary cortisol levels were higher at 2 years of age than in infancy in the reference group, were higher in girls than in boys at 2 years of age, and were higher in infants at the time of acute bronchiolitis than in healthy infants.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00817466.

Cortisol response to acute stress in asthma: Moderation by depressive mood

Both individuals with asthma and depression show signs of a dysregulated hypothalamus-pituitary-adrenal axis. However, little is known about the cortisol response to stress in the context of co-occurring asthma and depressive mood. Thirty-nine individuals with asthma and 41 healthy controls underwent a combined speech and mental arithmetic stressor. During the course of the laboratory session, salivary cortisol was collected 5 times, with 1 sample at 0min before the stressor and 4 samples at 0, 15, 30 and 45min after the stressor. Depressive mood in the past week was assessed with the Hospital Anxiety and Depression Scale at the beginning of the session. Depressive symptoms moderated cortisol response to the acute stressor, but only among asthmatic patients. Higher depressive mood was associated with a significant increase in cortisol, whereas low depressive mood was associated with no cortisol response. In healthy participants, depressive mood had no substantial effect on cortisol response to the stressor. These findings suggest that depressive mood and chronic inflammatory diseases such as asthma can interact to augment cortisol response to stress.

Reproducibility and utility of an overnight 0.25 mg dexamethasone suppression test as a marker for glucocorticoid sensitivity in children with asthma

PURPOSE

Inhaled corticosteroids (ICS) are the cornerstone of asthma treatment in children. However, there is considerable inter-individual variation in glucocorticoid sensitivity, leading to over- as well as undertreatment. A simple and fast test to predict glucocorticoid sensitivity would enable more tailored therapy in children with asthma.

AIM

To study reproducibility and utility of an overnight 0.25 mg dexamethasone suppression test (DST) with salivary cortisol levels as marker for glucocorticoid sensitivity in asthmatic children.

METHODS

23 children with atopic asthma were recruited for two overnight 0.25 mg DST's, 1 month apart.

RESULTS

Baseline cortisol levels correlated well between both tests. However, cortisol levels, change in cortisol levels or fractional suppression of cortisol levels after dexamethasone did not correlate between the two tests. Bland-Altman plots showed that the difference in salivary cortisol levels between test 1 and 2 of an individual patient could go up to 12 nmol/l, which is a clinically relevant difference. ICS dose did not correlate with baseline cortisol levels, height and BMI SDS.

CONCLUSION

The low-dose salivary DST test in its current form is not suitable for use in clinical practice in children with asthma, due to low reproducibility. Therefore, studies using the 0.25 mg salivary DST should be interpreted cautiously.

Children with asthma have significantly lower long-term cortisol levels in their scalp hair than healthy children

AIM

Noninvasive measurement of long-term cortisol levels is a useful way of evaluating the effect of chronic disease on the hypothalamic-pituitary-adrenal axis in children. The aim of this pilot study was to compare hair cortisol levels in children using inhaled corticosteroids for asthma and healthy children and to determine the association with short-term salivary cortisol levels.

METHODS

Cortisol levels were measured in the scalp hair and saliva of prepubertal children with asthma (n = 10) and without asthma (n = 10). Asthma control was assessed using an asthma questionnaire and pulmonary function tests.

RESULTS

The median (95% CI) cortisol level in the scalp hair of the children with asthma (2.0 pg/mg; 1.4-4.1) was significantly lower than the healthy children (4.3 pg/mg; 1.8-5.9). Morning salivary cortisol levels were significantly lower for the children with asthma (5.9 nmol/L; 3.2-11.1) than the healthy children (9.0 nmol/L; 4.4-31.6). There was no significant association between cortisol levels in hair and saliva.

CONCLUSION

Long-term cortisol levels were significantly lower in children with asthma than healthy children. Measuring long-term cortisol levels in scalp hair is an attractive, noninvasive tool that can evaluate the effect of asthma and its treatment on the hypothalamic-pituitary-adrenal axis.

The impact of asthma control on salivary cortisol level in adult asthmatics

Asthma is a chronic disease causing psychological stress which leads to the activation of hypothalamus-pituitary-adrenal axis. The purpose of this study is to compare morning salivary cortisol levels in persistent asthma patients according to their disease severities and control status. Total 206 adult asthma patients were recruited from four university hospitals. Spirometry, questionnaire of Asthma Quality of Life (AQOL) and Asthma Control Test (ACT) were completed, and saliva samples were collected prospectively to measure morning cortisol level. The mean patient age was 56.5±15.3 years with mean asthma duration of 9.1±11.1 years. Sixty five patents (31.6%) were classified as mild persistent asthma, and 141 patients (68.4%) were classified as moderate persistent asthma according to the Expert Panel Report 3. The mean predicted FEV1 was 88.8%±18.4%, and the methacholine PC20 was 9.6±8.5 mg/mL in all study population. The mean ACT score for all patients was 19.9±3.6, and there were 71 (34.5%) patients in poorly controlled and 135 (65.5%) in well controlled asthma. The poorly controlled asthma patients were characterized by significantly lower FEV1 (84.6%±17.6% vs 91.1%±18.5%, P=0.018), lower AQOL scores (46.0±13.9 vs 73.8±26.3, P<0.001), and lower salivary cortisol levels (0.14±0.08 vs 0.18±0.11 µg/dL, P=0.04) compared to well controlled asthma. The ACT score was significantly related to salivary cortisol levels (P=0.034) after adjusting for age. There was no significant difference in salivary cortisol levels (0.17±0.12 vs 0.16±0.08, P=0.725) when analyzed according to the dose of used corticosteroid and lung function. Asthma control status affects morning salivary cortisol level. Measuring the morning salivary cortisol level might be a simple and new way to assess asthma control status.

Longitudinal associations between infections and atopic disorders across childhood and dysregulated adrenocortical functioning in early adolescence

The present study sought to determine if exposure to common childhood medical problems (i.e., infections and atopic disorders [e.g., allergies, asthma]) may dysregulate the hypothalamic-pituitary-adrenal (HPA) axis. Longitudinal data from 96 youth were used to examine this possibility. Medical records were drawn from government databases indicating the frequency of visits to healthcare facilities for infections and atopic disorders from infancy to early adolescence. During early adolescence, participants provided salivary cortisol samples from awakening until bedtime over 2 consecutive days. Individuals with a history of increased number visits for infections across childhood displayed elevated levels of cortisol at awakening whereas individuals with childhood histories of visits for atopic disorders displayed blunted diurnal cortisol slopes. These findings build on previous research documenting associations between infections and atopic disorders and cortisol by identifying longitudinal linkages from early health problems to later HPA axis functioning.

Variance of melatonin and cortisol rhythm in patients with allergic rhinitis

OBJECTIVE

Allergic rhinitis is an IgE-mediated inflammatory disease which effects 10%-50% of the normal population. The mechanism of its formation and the circadian rhythm of cortisol and melatonin in allergic rhinitis have not been investigated.

STUDY DESIGN

Salivary levels of melatonin and cortisol were measured by radioimmunoassay in 35 newly diagnosed allergic rhinitis patients and in 23 control subjects matched for age and gender.

RESULTS

In the study group; amplitude, baseline and peak levels of salivary melatonin were significantly decreased compared with healty controls (p<0.001). No differences were found in the acrophase and the peak duration of salivary melatonin between the study and control groups (p>0.05). In the study subjects, the circadian rhythm of cortisol was flattened when compared with the control group. The amplitude and the 24h mean levels of salivary cortisol in the study group were significantly lower than in the control group and the acrophase was delayed in patients compared with control subjects (p<0.001).

CONCLUSION

The circadian rhythms of salivary melatonin and cortisol were found to be disrupted in patients with allergic rhinitis. These results may also be contributive data to explain the pathogenesis of allergic rhinitis and also they can be applicable as adjunctive therapeutic tools in the future and melatonin drugs might be an alternative in the therapy of resistant allergic rhinitis patients or allergic rhinitis patients who cannot use cortisol drugs.

The observed association between maternal anxiety and adolescent asthma: children of twin design suggest familial effects

Background

Previous studies indicate that maternal anxiety is associated with asthma in the adolescent child, but mechanisms are unclear.

Objective

To investigate the association between maternal anxiety and maternal, self- and register-based report of asthma in the adolescent child, and whether the association remains after control of familial confounding (shared environmental and genetic factors).

Method

From the Twin and Offspring Study of Sweden, 1691 mothers (1058 twins) and their adolescent child were included. The association between maternal self-reported anxiety (Beck Anxiety Inventory (BAI) and Karolinska Scales of Personality (KSP) somatic or psychic anxiety) and asthma based on subjective (maternal or child report) or objective (register-based diagnosis and medication) measures were analysed using logistic regression. The children-of-twins design was used to explore whether genes or environment contribute to the association.

Results

Maternal BAI anxiety (OR 2.02, CI 1.15–3.55) was significantly associated with adolescent asthma reported by the mother. Maternal KSP somatic anxiety (OR 1.74, CI 1.04–2.91) and psychic anxiety (OR 1.74, CI 1.05–2.86) was significantly associated with breathlessness reported by the adolescent child. In contrast, maternal anxiety was not associated with increased risk for the register-based outcomes of asthma diagnosis or medication. The results remained also after adjusting for covariates and the children-of-twins analyses which indicate that the association was due to familial confounding.

Conclusions

We found some associations between maternal anxiety and subjectively reported offspring asthma or breathlessness which may be due to familial effects. A likely candidate for explaining this familial confounding is heritable personality traits associated with both anxiety and subjective measures of asthma.

Melatonin and cortisol rhythm in patients with extensive nasal polyposis

PURPOSE

Extensive nasal polyposis is an inflammatory disease which effects 1%-4% of normal population. The mechanism of its formation and the circadian rhythm of cortisol and melatonin in ENP have not investigated.

MATERIALS AND METHODS

Salivary levels of melatonin and cortisol were measured by radioimmunoassay in 31 patients with extensive nasal polyposis and in 27 control subjects matched for age and gender. In both groups none of the subjects did not have obstructive sleep apnea.

RESULTS

The baseline and the peak levels of salivary melatonin in the extensive nasal polyposis group were significantly lower than in the control group (p<0.001). However, no differences were found in the acrophase and the peak duration of salivary melatonin between the study and control groups (p>0.05). The highest values of melatonin were recorded at 04:00 h in both the study and control groups. The amplitude and the 24 h mean levels of salivary cortisol in the extensive nasal polyposis group were significantly lower than in the control group (p<0.001). The acrophase was delayed by about 8 h in extensive nasal polyposis patients (p<0.001).

CONCLUSION

The circadian rhythms of salivary melatonin and cortisol were found to be disrupted in patients with extensive nasal polyposis. These results may be applicable as therapeutic tools in the future and melatonin drugs might be useful in the therapy of nasal polyposis like cortisol drugs.

Organophosphate pesticide environmental exposure: analysis of salivary cholinesterase and carboxilesterase activities in preschool children and their mothers

A pilot study was conducted to evaluate the usefulness of salivary cholinesterase and carboxylesterase as biomarkers of exposure to environmental organophosphate pesticides. Ninety samples were obtained from women and 62 samples from their preschool-aged children who live near an agricultural area of the Upper Valley of the Negro River (Patagonia, Argentina) where pesticides are applied 6 months a year. Each participant donated two samples under similar conditions: one in the pre-exposure period and another during the pulverization period. Demographic information, potential confounders, and risk behaviors were registered. Active or passive smoking had no effect on these enzyme activities in either group. During the pulverization period, cholinesterase activity was not detectable in 76% of the children's samples and 23% of the mothers' samples. Comparing samples collected during the pulverization period with respect to the pre-pulverization period, the average mother and child cholinesterase activity decreased by 65.7% (p < 0.001) and 85.8% (p < 0.001), respectively. Also, mother and child carboxylesterase activity decreased by 27.5% (p < 0.001) and 41.9% (p < 0.01), respectively. Child carboxylesterase activity in the pulverization period was associated to the habit of eating dust outdoors (p < 0.01). The most frequent inhibition levels observed for cholinesterase and carboxylesterase activity were between 70-100% and 0-29%, respectively, in both groups studied. This shows that at the same level of exposure, cholinesterase was more sensitive to inhibition than carboxylesterase. Therefore, carboxylesterase might more properly reflect the degree of environmental organophosphate exposure and may have potential as a novel tool for biomonitoring.