Associations Between Maternal Distress, Cortisol Levels, and Perinatal Outcomes

OBJECTIVE

Stress during pregnancy may decrease gestational age at birth and birth size. We aimed to investigate the associations between maternal subjective stress measures, salivary cortisol, and perinatal outcomes.

METHODS

A cohort of pregnant women (n = 1693) was recruited from eight antenatal care clinics in Stockholm, Sweden. Questionnaires on subjective distress (perceived stress, worry, depression symptoms, sleep quality) and saliva samples for cortisol measurement (morning and evening) were collected in early and late pregnancy. Perinatal outcomes were birth weight, birth length, gestational age, and birth weight for gestational age. We used linear regression to estimate associations adjusted for maternal characteristics.

RESULTS

All associations between subjective distress and cortisol levels were close to null and nonsignificant, for example, exp(β) = 1.001 (95% confidence interval = 0.995 to 1.006) for the morning cortisol level and perceived stress in early pregnancy. Likewise, most associations between distress (subjective and cortisol) and perinatal outcomes were weak and not statistically significant, for example, β = 1.95 (95% confidence interval = -4.16 to 8.06) for perceived stress in early pregnancy and birth weight. An exception was a statistically significant association between birth weight for gestational age and depression symptoms in early pregnancy, with somewhat higher weight with more symptoms (β = 0.08; 95% CI = 0.04 to 0.13). The results were similar for stress in early and late pregnancy.

CONCLUSIONS

We found no association between subjective distress and cortisol measures irrespective of when in pregnancy the measures were taken. Furthermore, we found no evidence for a longitudinal association between psychological measures of stress or cortisol with lower birth weight, birth weight for gestational age, or gestational age.

1057Addressing challenges in life-course epidemiology: established and novel approaches using big data and twin/family studies

Focus and outcomes for participants

Long periods between exposures and outcomes pose a number of challenges for life course epidemiological research, including unmeasured confounding factors (e.g.; familial factors) and mediation by other covariates, which make it difficult to unequivocally establish associations let alone causality. In this symposium we will present a number of different studies based on big data utilizing a variety of methods to overcome some of the issues encountered in research across long time frames or generations. Our focus will be on the different methods, the solutions they provide as well as their limitations. The methods presented were applied in the context of life course epidemiology and include: mediation analyses; genetic epidemiology; well-established and novel family designs including twins, siblings and cousins, and a method comparable to Mendelian randomization - ICE FALCON (Inference on Causation from Examination of Familial Confounding) which is part of a more general approach called ICE CRiSTAL (Inference on Causation from Examining Changes in Regression coefficients in STatistical AnaLsyes). The intended outcomes for the audience are to increase awareness of the challenges imposed by the data frequently used in this field of research and present possible solutions to (at least partly) address those. It is our intention to generate discussion and encourage other researchers to share their experiences and solutions to increase knowledge collectively.

Rationale for the symposium, including for its inclusion in the Congress

The main theme of the conference is ‘Methodological Innovations in Epidemiology’. Our symposium includes six different methods to strengthen causal inferences in epidemiology. While some of the presented methods are well established in classic epidemiology research (i.e. mediation analyses), others are more commonly found in different disciplines such as the expanding genetic epidemiology field (e.g. alternative twin designs and measured genetic risk approaches). In addition, we are presenting a new method for making inference about causation developed by Prof. John Hopper and Dr Shuai Li and co-workers called ICE FALCON, which applies to twin and family data and is part of a more general approach called ICE CRiSTAL. These methods use observational data to infer or rebut causality between measured variables, similar to Mendelian randomization (without relying on genetic information or strong assumptions). All the work presented is either nearing publication or has been published in the last two years and each presenter is intimately involved with the analysis and methods they will be presenting. Beyond a range of methods and study designs we have also a diversity of researchers and research questions in our symposium by including: researchers at different stages in their career and from around the world (ranging from early Postdoctoral Fellows over Senior Research Fellows/Assistant professors to Professors); a variety of research questions and diseases; and a range of population context including Indigenous Australians, babies, children, and adults, in order to appeal to a wider audience.

Presentation program

6 talks of 8 minutes each with 2 minutes for questions followed by a general discussion facilitated by the chair.

Names of presenters

Dr Miriam A Mosing1,2

1254Comorbidity of atopic diseases and gastroesophageal reflux in adults: a co-twin control study

Background

Gastroesophageal reflux disease (GERD) is the most common non-allergic comorbidity in adults with asthma, however comorbidity with other atopic diseases such as eczema and hayfever is unclear. The objective was to assess the comorbidity of GERD with atopic diseases in adults, and to investigate possible mechanisms including genetic and affective factors.

Methods

A co-twin control study harnessing 46 583 adult Swedish twins. Questionnaires on health status were linked to national patient and prescribed drug register data. Within twin-pair comparisons were made between unpaired, monozygotic (MZ) and dizygotic (DZ) twins to assess common genetic liability. Affective traits (depression, anxiety and neuroticism) were added to models to assess their role in comorbidity.

Results

The risk of GERD in those with asthma was OR1.52 (95% CI 1.38, 1.68); hayfever OR1.22 (95%CI 1.12, 1.34); and eczema OR1.23 (95%CI 1.10, 1.38). Within twin-pair associations attenuated in decreasing order of shared genetics for all atopic diseases e.g. self-report asthma with GERD: DZ twins adjOR1.41 (95%CI 0.96, 2.08), MZ twins adjOR1.24 (95%CI 0.82, 1.87). Adjusting for affective traits only slightly attenuated the comorbidity associations.

Conclusions

GERD is a common comorbidity in adults with asthma, hayfever and/or eczema. We found evidence for shared genetic factors but not for affective traits.

Key messages

GERD is a common comorbidity not only in adults with asthma, but also in adults with eczema or hayfever. Twin research has revealed evidence for a common genetic liability to explain comorbidity.

Cognitive ageing is premature among a community sample of optimally treated people living with HIV

OBJECTIVES

Evidence of premature cognitive ageing amongst people living with HIV (PLHIV) remains controversial due to previous research limitations including underpowered studies, samples with suboptimal antiretroviral access, varying rate of virological control, high rate of AIDS, over-representation of non-community samples, and inclusion of inappropriate controls. The current study addresses these limitations, while also considering mental health and non-HIV comorbidity burden to determine whether PLHIV showed premature cognitive ageing compared with closely comparable HIV-negative controls.

METHODS

This study enrolled 254 PLHIV [92% on antiretroviral therapy; 84% with HIV RNA < 50 copies/mL; 15% with AIDS) and 72 HIV-negative gay and bisexual men [mean (SD) age = 49 (10.2) years] from a single primary care clinic in Sydney, Australia. Neurocognitive function was evaluated with the Cogstate Computerized Battery (CCB) at baseline and 6 months after. Linear mixed-effects (LME) models examined main and interaction effects of HIV status and chronological age on the CCB demographically uncorrected global neurocognitive z-score (GZS), adjusting for repeated testing, and then adjusting sequentially for HIV disease markers, mental health and comorbidities.

RESULTS

HIV status and age interacted with a lower GZS (β = -0.43, P < 0.05). Higher level of anxiety symptoms (β = -0.11, P < 0.01), historical AIDS (β = -0.12, P < 0.05) and historical HIV brain involvement (β = -0.12, P < 0.05) were associated with lower GZS.

CONCLUSIONS

We found a robust medium-sized premature ageing effect on cognition in a community sample with optimal HIV care. Our study supports routine screening of cognitive and mental health among PLHIV aged ≥ 50 years.

Identifying preventable risk factors for hospitalised asthma in young Aboriginal children: a whole-population cohort study

BACKGROUND

Australia has one of the highest rates of asthma worldwide. Indigenous children have a particularly high burden of risk determinants for asthma, yet little is known about the asthma risk profile in this population.

AIM

To identify and quantify potentially preventable risk factors for hospitalised asthma in Australian Aboriginal children (1-4 years of age).

METHODS

Birth, hospital and emergency data for all Aboriginal children born 2003-2012 in Western Australia were linked (n=32 333). Asthma was identified from hospitalisation codes. ORs and population attributable fractions were calculated for maternal age at birth, remoteness, area-level disadvantage, prematurity, low birth weight, maternal smoking in pregnancy, mode of delivery, maternal trauma and hospitalisations for acute respiratory tract infection (ARTI) in the first year of life.

RESULTS

There were 705 (2.7%) children hospitalised at least once for asthma. Risk factors associated with asthma included: being hospitalised for an ARTI (OR 4.06, 95% CI 3.44 to 4.78), area-level disadvantage (OR 1.58, 95% CI 1.28 to 1.94), being born at <33 weeks' gestation (OR 3.30, 95% CI 2.52 to 4.32) or birth weight <1500 g (OR 2.35, 95% CI 1.39 to 3.99). The proportion of asthma attributable to an ARTI was 31%, area-level disadvantage 18%, maternal smoking 5%, and low gestational age and birth weight were 3%-7%. We did not observe a higher risk of asthma in those children who were from remote areas.

CONCLUSION

Improving care for pregnant Aboriginal women as well as for Aboriginal infants with ARTI may help reduce the burden of asthma in the Indigenous population.

Towards non-conventional methods of designing register-based epidemiological studies: An application to pediatric research

AIMS

Various epidemiological designs have been applied to investigate the causes and consequences of fetal growth restriction in register-based observational studies. This review seeks to provide an overview of several conventional designs, including cohort, case-control and more recently applied non-conventional designs such as family-based designs. We also discuss some practical points regarding the application and interpretation of family-based designs.

METHODS

Definitions of each design, the study population, the exposure and the outcome measures are briefly summarised. Examples of study designs are taken from the field of low birth-weight research for illustrative purposes. Also examined are relative advantages and disadvantages of each design in terms of assumptions, potential selection and information bias, confounding and generalisability. Kinship data linkage, statistical models and result interpretation are discussed specific to family-based designs.

RESULTS

When all information is retrieved from registers, there is no evident preference of the case-control design over the cohort design to estimate odds ratios. All conventional designs included in the review are prone to bias, particularly due to residual confounding. Family-based designs are able to reduce such bias and strengthen causal inference. In the field of low birth-weight research, family-based designs have been able to confirm a negative association not confounded by genetic or shared environmental factors between low birth weight and the risk of asthma.

CONCLUSIONS

We conclude that there is a broader need for family-based design in observational research as evidenced by the meaningful contributions to the understanding of the potential causal association between low birth weight and subsequent outcomes.

The health and wellbeing of Australian farmers: a longitudinal cohort study

Background

Isolation, long work days, climate change and globalization are just some of the many pressures that make farming a vulnerable occupation for incurring mental health issues. The objective of this study was to determine whether farming in Australia is associated with poorer wellbeing, physical and mental health, and less health service use.

Methods

The Australian Rural Mental Health Study, a longitudinal cohort study was analysed over four time points comparing farmers with non-farming workers (n = 1184 at baseline). Participants were recruited from rural NSW, Australia. A number of physical, mental health, wellbeing, service use outcomes were assessed using generalised estimating equations including all waves in each model. Barriers to seeking help were also assessed.

Results

Farmers who lived remotely reported worse mental health (β −0.33, 95 % CI −0.53, −0.13) and wellbeing (β −0.21(95 % CI −0.35, −0.06) than remote non-farm workers regardless of financial hardship, rural specific factors eg drought worry, or recent adverse events. All farmers were no different to non-farming workers on physical health aspects except for chronic illnesses, where they reported fewer illnesses (OR 0.66, 95 % CI 0.44, 0.98). All farmers were half as likely to visit a general practitioner (GP) or a mental health professional in the last 12 months as compared to non-farm workers regardless of location (OR 0.59, 95 % CI 0.35, 0.97). Rural workers felt that they preferred to manage themselves rather than access help for physical health needs (50 %) or mental health needs (75 %) and there was little difference between farmers and non-farm workers in reasons for not seeking help.

Conclusions

Remoteness is a significant factor in the mental health and wellbeing of farmers, more so than financial stress, rural factors and recent adverse events. Creative programs and policies that improve access for farmers to GPs and mental health professionals should be supported.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-016-3664-y) contains supplementary material, which is available to authorized users.

Neuropsychological Dysfunction in HIV Infection:A Review

FIfty-six studies which used neuropsychological tests to investigate areas of function affected by central nervous system dysfunction in HIV were reviewed. Only studies which compared the performance of HIV + subjects to HIV - controls using analysis of variance techniques were included. The results are examined in terms of broad neuropsychological function domains, and are examined separately for asymptomatic and symptomatic subjects. Studies which did and did not find significant differences between HIV + and HIV - subjects were compared in terms of various confounding factors such as risk groups, number of tests, sample size and subject characteristics. There was evidence for some dysfunction among subjects who are otherwise asymptomatic in the areas of verbal memory (27% of studies), executive function (43%), motor performance (20%) and information processing (44%). Studies of subjects with more advanced HIV infection showed consistent evidence of abnormal functioning in the areas of verbal (48% of studies) and visual memory (43%), executive functioning (71%), complex attention (62%), motor performance (37%) and information processing (69%). These deficits occurred prior to the onset of clinically apparent dementia. There were no consistent significant differences between studies which did and did not find significant differences between HIV + and HIV - subjects in terms of most of the confounding variables investigated, although studies of ASX subjects were more likely to find differences between HIV + subjects and controls with larger neuropsychological test battereies. However, much of the variation in results due to the neuropsychological tests used. In many cases, tests which relied on functions with a frontal lobe component were more likely to find significant results.

Early syphilis presenting as a painful polyradiculopathy in an HIV positive individual

Neurosyphilis and neurological complications from syphilis may be commoner in HIV disease. With outbreaks of early syphilis in HIV positive individuals being observed over recent years, rare neurological manifestations of secondary syphilis will be observed more commonly. We describe a case of an HIV positive individual whose first presenting feature of early syphilis was a polyradiculopathy.

HIV-1 reverse transcriptase sequence in plasma and cerebrospinal fluid of patients with AIDS dementia complex treated with Abacavir

OBJECTIVE

To assess HIV-1 RNA levels and the relationship between HIV-1 reverse transcriptase (RT) genotype from plasma and cerebrospinal fluid (CSF) during treatment with abacavir (Ziagen, ABC) or placebo in combination with stable background therapy (SBG) in subjects with AIDS dementia complex (ADC) (study CNA3001).

DESIGN

One-hundred and five HIV-1 infected adults with ADC were randomized to receive either ABC (600 mg twice daily) or ABC-matched placebo (twice daily) in addition to SBG for 12 weeks.

METHODS

Plasma and CSF were collected for population sequencing at baseline and week 12 (CSF optional). Sequences were analyzed for mutations associated with resistance to nucleoside reverse transcriptase inhibitors (NRTI).

RESULTS

Sixty out of sixty-seven subjects with baseline plasma HIV-RT sequence data harbored virus with > or = 1 NRTI-associated mutations; 50 out of 67 had the M184V mutation. At week 12, more subjects in the ABC group had plasma HIV-1 RNA < or = 400 copies/ml than the SBG group (46% versus 13%, P = 0.002). Non-response to ABC was associated with multiple baseline zidovudine (ZDV)/stavudine (d4T)-associated mutations. Baseline RT mutation patterns differed in 14 out of 21 (67%) paired samples from plasma and CSF. Four subjects experienced > 1 log10 copies/ml reductions in CSF HIV-1 RNA, two in the absence of reductions in plasma HIV-1 RNA and two with undetectable plasma HIV-1 RNA at baseline.

CONCLUSIONS

Substantial decreases in plasma and CSF HIV-1 RNA following addition of ABC were not precluded by baseline HIV-1 NRTI-associated mutations, including the M184V mutation, but non-responders commonly harbored multiple ZDV/d4T-associated mutations. HIV-1 RNA responses and RT genotype appear to be discordant between CSF and plasma in some subjects.

Varied tropism of HIV-1 isolates derived from different regions of adult brain cortex discriminate between patients with and without AIDS dementia complex (ADC): evidence for neurotropic HIV variants

A number of infected individuals develop neuropathological disorders, such as AIDS dementia complex (ADC), as a consequence of HIV/AIDS. The biological features governing HIV entry and tropism in different brain cell types remain unclear, as do the genetics of the virus regulating these events and the neuropathogenic processes within the brain tissues. HIV-1 was isolated from the right and left parietal, occipital, and frontal lobes of the brain cortex of three HIV-1-infected patients: two with ADC and one without. The viral strains were studied from the innate tissues and various primary cell cultures. The kinetics and tropism of viral strains from different brain regions showed clear differences on various primary cell types (monocytes, monocyte-derived macrophages, and T cells), which could discriminate between biological behavior of HIV-1 strains from patients with and without ADC. The variable effect of different donor cells on tropism was also clearly evident. The majority (with a few exceptions) of isolates from different brain regions of all three patients used CCR5 as coreceptor for entry. The consistent CCR5 use, macrophage tropism, and non-syncytium-inducing phenotype were the main characteristics of the brain-derived HIV-1 strains from all three patients. Importantly, viral strains derived directly from innate brain tissue of the patient without ADC showed some differences from the cultured variants of the same patient, whereas those from brain tissue of the patients with ADC were more similar to the culture-adapted strains. This suggests that the emergence of primary cell type-adapted isolates during ADC may play a crucial role in the development and progression of the neuropathology associated with ADC. The different genotypes residing in different areas of brain combined with their differential tropism and coreceptor use suggest that neurotropic variants exist that may be governing the neurological manifestation of HIV disease in infected patients.

Evidence for independent development of resistance to HIV-1 reverse transcriptase inhibitors in the cerebrospinal fluid

OBJECTIVES

To delineate and compare the nature and frequency of mutations known to confer resistance to HIV-1 nucleoside reverse transcriptase inhibitors in the cerebrospinal fluid (CSF) and blood compartments.

METHODS

Fifty-three paired CSF and plasma specimens had been prospectively collected and stored from 49 HIV-1 infected patients. These were tested using a commercially available line probe assay which allows the simultaneous detection of wild-type and drug selected variants conferring resistance to one or more drugs: zidovudine, didanosine, zalcitabine, and lamivudine.

RESULTS

Of the 53 (58%) paired samples, 31 could be amplified by nested PCR. The current assay's limitation for use with CSF is highlighted as 91% of blood samples amplified compared with 60% of CSF samples showing the assays inability to amplify viral loads below 1000 copies/ml. Of the 31 patients 21 (68%) had identical resistance patterns in the CSF and plasma; the other 10 (32%) patients had a resistance profile in the CSF that was different from that in their plasma. Of these, three samples demonstrated amino acid changes associated with high level zidovudine resistance in the CSF but the blood sample remained genotypically sensitive. Nine samples demonstrated resistance in blood but remained wild-type in the CSF. Resistant genotypes were detected in CSF for all nucleosides except didanosine.

CONCLUSIONS

Differences in the positions and frequencies of wild-type and drug selected variants in specimens derived from the CSF and blood compartments were detected in a significant number of patients; this argues for the independent development of drug resistance in the CNS in some patients. These findings may have important implications in guiding antiretroviral therapy in HIV-1 infection.

Nitric oxide synthetase and Helicobacter pylori in patients undergoing appendicectomy

BACKGROUND: This study was designed to determine whether Helicobacter pylori forms part of the normal microenvironment of the appendix, whether it plays a role in the pathogenesis of acute appendicitis, and whether it is associated with increased expression of inducible nitric oxide synthetase (iNOS) in appendicular macrophages. METHODS: Serology for H. pylori was performed on 51 consecutive patients undergoing emergency appendicectomy. Appendix samples were tested for urease activity, cultured and stained for H. pylori, graded according to the degree of inflammatory infiltrate, and probed immunohistochemically for iNOS expression. RESULTS: The mean age of the patients was 21 (range 7-51) years. Seventeen patients (33 per cent) were seropositive for H. pylori but no evidence of H. pylori was found in any appendix specimen. However, an enhanced inflammatory cell infiltration was observed in seropositive patients (P < 0.04) and the expression of macrophage iNOS in the mucosa of normal and inflamed appendix specimens was increased (P < 0.01). CONCLUSION: H. pylori does not colonize the appendix and is unlikely to be a pathogenic stimulus for appendicitis. Priming effects on mucosal immunology downstream from the foregut may occur after infection with H. pylori.

HIV infection of macrophages and pathogenesis of AIDS dementia complex: interaction of the host cell and viral genotype

AIDS dementia complex (ADC) develops in only a third of HIV-infected patients who progress to AIDS. Macrophages and microglial cells are the major cellular sites of productive HIV replication in brain. Using 11 blood isolates of HIV from asymptomatic patients there was marked variation in tropism and the level of productive infection in recently adherent monocytes and monocyte-derived macrophages cultured in vitro. However, less variation was seen with 19 blood isolates from advanced HIV infection and 11 postmortem tissue isolates from brain, cerebrospinal fluid, spleen, and lung. Newly adherent monocytes expressed CCR5 in all seven patients tested, consistent with their susceptibility to infection but not explaining the above variability. There is, also marked regional variability in neuropathology in the brain of patients with ADC. We have demonstrated that there was marked variation in the V3 sequences of HIV clones from different regions of the cortex of a patient with ADC, suggesting independent evolution of HIV replication in brain. Furthermore, production of the neurotoxin quinolinic acid from HIV-infected macrophages varied, depending on the host and source of HIV isolate. Hence variations in viral genotype, production by infected macrophages, and subsequent toxin production may contribute to the variability in neuropathology between individuals and between different regions of the brain in the same individual.

Radionuclide hepatobiliary scanning in patients with AIDS-related sclerosing cholangitis

Biliary disease, primarily manifesting as papillary stenosis or sclerosing cholangitis, is being increasingly recognized as a problem in the acquired immunodeficiency syndrome (AIDS) and may be amenable to specific treatment. Ultrasound, followed by endoscopic retrograde cholangiopancreatography (ERCP) for definitive diagnosis, is currently the prime mode of investigation of suspected hepatobiliary diseases in AIDS. There are few published reports of the use of radionuclide cholescintigraphy in the assessment of these patients. This report presents Tc-99m DISIDA cholescintigraphy data from three patients with AIDS-related hepatobiliary disease confirmed by ERCP. Radionuclide cholescintigraphy was abnormal in all three patients. In two of the subjects, there was focal duct dilation with strictures in the biliary tree. The third patient demonstrated diffuse hepatic parenchymal retention with marked delay in tracer washout. Two of the subjects, treated with specific anticryptosporidial therapy, subsequently underwent progress cholescintigraphy. In one of these patients with initial diffuse parenchymal retention, there was marked improvement in scan appearances. The second patient with initial duct dilation had no significant change in scan appearances, but quantitative analysis did demonstrate improvement in hepatobiliary tracer clearance rate. In conclusion, although ERCP remains the gold standard in the diagnosis of AIDS-related biliary disease, radionuclide cholescintigraphy may be a useful modality in these patients as a screening test before proceeding to more expensive and invasive techniques. In addition, quantitative analysis of cholescintigraphy may allow assessment of patient response to specific antimicrobial or surgical intervention.

Management of the neurologic complications of HIV infection and AIDS

The approach to neurologic diagnosis and management of HIV-infected and AIDS patients follows that used in general neurologic practice but takes into account the altered probabilities of differential diagnosis in this group of patients. Clinical and neurodiagnostic evaluations, when pursued with a background understanding of the spectrum of neurologic disorders affecting these patients, allow accurate diagnosis in the great majority of patients. As with other aspects of AIDS, this is an important exercise, as many of these neurologic disorders can be treated with gratifying relief of morbidity or prevention of death.

The brain in AIDS: central nervous system HIV-1 infection and AIDS dementia complex

Infection with human immunodeficiency virus type 1 (HIV-1) is frequently complicated in its late stages by the AIDS dementia complex, a neurological syndrome characterized by abnormalities in cognition, motor performance, and behavior. This dementia is due partially or wholly to a direct effect of the virus on the brain rather than to opportunistic infection, but its pathogenesis is not well understood. Productive HIV-1 brain infection is detected only in a subset of patients and is confined largely or exclusively to macrophages, microglia, and derivative multinucleated cells that are formed by virus-induced cell fusion. Absence of cytolytic infection of neurons, oligodentrocytes, and astrocytes has focused attention on the possible role of indirect mechanisms of brain dysfunction related to either virus or cell-coded toxins. Delayed development of the AIDS dementia complex, despite both early exposure of the nervous system to HIV-1 and chronic leptomeningeal infection, indicates that although this virus is "neurotropic," it is relatively nonpathogenic for the brain in the absence of immunosuppression. Within the context of the permissive effect of immunosuppression, genetic changes in HIV-1 may underlie the neuropathological heterogeneity of the AIDS dementia complex and its relatively independent course in relation to the systemic manifestations of AIDS noted in some patients.