Investigation of the relationship between smoking and appendicitis in Australian twins

An observational study on lifestyle and environmental risk factors in patients with acute appendicitis

Purpose

Acute appendicitis is a common abdominal emergency worldwide. This study aimed at characterizing environmental risk factors influencing the development and severity of acute appendicitis.

Methods

Patients from a Belgian acute appendicitis cohort (n = 374) and healthy controls from the 500 functional genomics (500FG) cohort (n = 513) were compared. Individuals with a history of appendectomy (n = 1067) and without a history of appendectomy (n = 8656) were available from the Nijmegen Biomedical Study (NBS). Questionnaires on demographics, lifestyle and environment were available. Binary logistic regression was used for prediction models.

Results

Fifteen risk factors for developing acute appendicitis were identified. Binary logistic regression showed that 7 were independent risk factors: family history of acute appendicitis, having grown up in a rural environment, having a lower education, probiotic use as well as antibiotic use increased the risk of developing appendicitis. Fruit and fiber-rich vegetable consumption decreased the risk. Findings on vegetable consumption, smoking and level of education were replicated in the NBS population. Independent risk factors for complicated appendicitis were being male, higher age, and a delay to diagnosis of more than 48 h.

Conclusions

Environmental exposures influence the risk of developing appendicitis. Further research into these factors is needed.

Non-culture-based studies of the appendiceal microbiota: a systematic review

Aims: To review studies examining the appendiceal microbiota and microbial changes in acute appendicitis. Methods: After a systematic literature search, 11 studies examining the appendiceal microbiota (414 samples) using non-culture-based methods were included. Results: The appendiceal microbiota showed decreased α-diversity compared with fecal microbiota. Inflamed and uninflamed appendices showed differences in β-diversity, and there was an increased abundance of oral-associated bacteria in inflamed versus uninflamed appendices. Conclusion: The appendiceal microbiota exhibits lower α-diversity than the fecal microbiota, with an increased abundance of oral-associated bacteria. Compared with uninflamed appendices, the appendix microbiota in acute appendicitis also showed increased abundance of oral-associated bacteria, but no bacterial profile unique to either complicated or uncomplicated appendicitis was found.

Maternal Smoking During Pregnancy and Risk of Appendicitis in the Offspring

BACKGROUND

Existing evidence on the link between smoking and appendicitis is scarce and ambiguous. We therefore conducted a population-based cohort study in Denmark to investigate whether smoking during pregnancy is associated with an increased risk of appendicitis in offspring.

METHODS

We used the Danish Birth Registry to include all singletons born during 1991-2017 and to identify maternal smoking status during pregnancy. We followed the children from birth until date of appendicitis, emigration, death, or administrative end of study (31 December 2018), whichever came first. We calculated crude and adjusted hazard ratios (HRs) of appendicitis with 95% confidence intervals (CIs) comparing children of mothers who smoked during pregnancy to children of nonsmokers. Further, we conducted a bias analysis and sibling analysis.

RESULTS

We included 1,659,526 singletons of whom 19% were born to mothers who smoked during pregnancy. After maximum 28 years of follow-up, hazard rates for children of smokers were slightly higher than for children of nonsmokers [adjusted HR: 1.07 (95% CI = 1.04, 1.10)]. Stratification by sex revealed no association for males [adjusted HR: 1.02 (95% CI = 0.99, 1.06)], but a higher HR for females [adjusted HR: 1.13 (95% CI = 1.09, 1.18)]. This association increased with increasing length of follow-up, indicating that the association may be mediated by later-life exposures. The bias analysis indicated that misclassification of maternal smoking could attenuate a true association, while the sibling analysis showed no association.

CONCLUSIONS

Maternal smoking during pregnancy and appendicitis in the offspring may be associated.

Appendectomy and Future Risk of Microscopic Colitis: A Population-Based Case-Control Study in Sweden

BACKGROUND AND AIMS

Microscopic colitis (MC) is an inflammatory bowel disease and a common cause of chronic diarrhea. Appendectomy has been suggested to have immunomodulating effects in the colon, influencing the risk of gastrointestinal disease. The relationship between appendectomy and MC has only been sparsely studied.

METHODS

This was a case-control study based on the nationwide ESPRESSO (Epidemiology Strengthened by histoPathology Reports in Sweden) cohort, consisting of histopathological examinations in Sweden, linked to national registers. Patients with MC were matched to population controls by age, sex, calendar year of biopsy, and county of residence. Data on antecedent appendectomy and comorbidities were retrieved from the Patient Register. Unconditional logistic regression models were conducted presenting odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for country of birth and matching factors. Further subanalyses were made based on MC subtypes (lymphocytic colitis and collagenous colitis), follow-up time postappendectomy and severity of appendicitis.

RESULTS

The study included 14,520 cases of MC and 69,491 controls, among these 7.6% (n = 1103) and 5.1% (n = 3510), respectively, had a previous appendectomy ≥1 year prior to MC or matching date. Patients with a previous appendectomy had an increased risk of MC in total (OR, 1.50; 95% CI, 1.40-1.61) and per the collagenous colitis subtype (OR, 1.67; 95% CI, 1.48-1.88) or lymphocytic colitis subtype (OR, 1.42; 95% CI, 1.30-1.55). The risk remained elevated throughout follow-up, and the highest risk was observed in noncomplicated appendicitis.

CONCLUSIONS

This nationwide case-control study found a modestly increased risk of developing MC following appendectomy.

Association of Appendicitis Incidence With Warmer Weather Independent of Season

IMPORTANCE

Acute appendicitis is a common cause of abdominal pain and the most common reason for emergency surgery in several countries. Increased cases during summer months have been reported.

OBJECTIVE

To investigate the incidence of acute appendicitis by considering local temperature patterns in geographic regions with different climate over several years.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used insurance claims data from the MarketScan Commercial Claims and Encounters Database and the Medicare Supplemental and Coordination of Benefits Database from January 1, 2001, to December 31, 2017. The cohort included individuals at risk for appendicitis who were enrolled in US insurance plans that contribute data to the MarketScan databases. Cases of appendicitis in the inpatient, outpatient, and emergency department settings were identified using International Classification of Diseases, Ninth Revision, Clinical Modification or International Statistical Classification of Diseases, Tenth Revision, Clinical Modification diagnosis codes. Local weather data were obtained for individuals living in a metropolitan statistical area (MSA) from the Integrated Surface Database. Associations were characterized using a fixed-effects generalized linear model based on a negative binomial distribution. The model was adjusted for age, sex, and day of week and included fixed effects for year and MSA. The generalized linear model was fit with a piecewise linear model by searching each 0.56 °C in temperature for change points. To further isolate the role of temperature, observed temperature was replaced with the expected temperature and the deviation of the observed temperature from the expected temperature for a given city on a given day of year. Data were analyzed from October 1, 2021, to July 31, 2022.

MAIN OUTCOMES AND MEASURES

The primary outcome was the daily number of appendicitis cases in a given city stratified by age and sex, with mean temperature in the MSA over the previous 7 days as the independent variable.

RESULTS

A total of 450 723 744 person-years at risk and 689 917 patients with appendicitis (mean [SD] age, 35 [18] years; 347 473 male [50.4%] individuals) were included. Every 5.56 °C increase in temperature was associated with a 1.3% increase in the incidence of appendicitis (incidence rate ratio [IRR], 1.01; 95% CI, 1.01-1.02) when temperatures were 10.56 °C or lower and a 2.9% increase in incidence (IRR, 1.03; 95% CI, 1.03-1.03) for temperatures higher than 10.56 °C. In terms of temperature deviations, a higher-than-expected temperature increase greater than 5.56 °C was associated with a 3.3% (95% CI, 1.0%-5.7%) increase in the incidence of appendicitis compared with days with near-0 deviations.

CONCLUSIONS AND RELEVANCE

Results of this cohort study observed seasonality in the incidence of appendicitis and found an association between increased incidence and warmer weather. These results could help elucidate the mechanism of appendicitis.

Patient backgrounds and short‐term outcomes of complicated appendicitis differ from those of uncomplicated appendicitis

Background

Appendicitis is classified as either complicated (CA) or uncomplicated (UA). Some authors have shown that the epidemiologic trends of CA and UA may differ. The aim of this study was to clarify differences in backgrounds and surgical outcomes between CA and UA patients.

Methods

This study was a cohort study. We extracted case data from the Japanese Diagnosis Procedure Combination (DPC) database from January 2014 to December 2017. Patients were classified into three groups, depending on whether they underwent emergency appendectomy for CA (CA group), emergency appendectomy for UA (UA group), or elective appendectomy (EA group). We evaluated patient characteristics and surgical outcomes for each group.

Results

We included 89,355 adult patients in the study, comprising 29,331 CA, 48,691 UA, and 11,333 EA patients. Old age, larger body mass index, smoking, and medication with antidiabetic drugs, oral corticosteroids, oral antiplatelet drugs, and oral anticoagulant drugs were independent risk factors for CA. The percentage of CA increased with age. In‐hospital mortality (0.15%, 0.02%, and 0.00%) and 30‐d mortality (0.09%, 0.01%, and 0.00%), respectively, of CA patients were significantly higher than those of the UA and EA groups. The duration of postoperative antibiotic administration, duration of fasting, and time before removal of a prophylactic drain were significantly longer in the CA group than in the UA and EA groups.

Conclusion

Backgrounds and treatment outcomes of CA and UA patients after emergency surgery are entirely different. Thus, the treatment strategy of CA and UA patients should differ accordingly.

Seasonal variation of acute appendicitis: An Armed Forces experience of high altitude

Background

Lifetime prevalence of Acute Appendicitis is about 6-7%.The seasonal variation is nearly an established fact with most of the studies suggesting that cases are more in summer and during the rainy season. There are few studies globally for evaluating the impact of altitude and temperature on the incidence of acute appendicitis. In India no such study has been reported. With this in view, a study was conducted on the incidence of acute appendicitis to evaluate the effect of absolute temperature in high altitudes >10000 ft.

Methods

Retrospective data collected for a period of five years from 2015 to 2019 for the three centres of Armed Forces, located at high altitude 10,500, 11,500 and 12,000 ft respectively and the three temperature categories viz.< 0 °C, 0-20 °C and >20 °C were made to infer if there is any correlation between these parameters.

Results

A total of 317 cases were operated in a period of 05 yrs at the three centres. In the three categories of temperature viz < 0 °C, 0-20 °C and >20 °C the total number of cases were 84,124 and 109 respectively over period of 5 yrs. The proportion of cases were maximum at altitude of 12000 ft. On evaluation of the effect of altitude and absolute temperature positive correlation is found.

Conclusion

The analysis of the maiden study that was conducted for high altitude and extreme cold climate in India indicated a positive correlation of the altitude and the effect of absolute temperature on the occurrence of cases of Acute Appendicitis.

Appendiceal neoplasm incidence and mortality rates are on the rise in Australia

OBJECTIVES

The study aimed to examine the incidence and mortality rates of appendiceal neoplasms (ANs) in Australia.

METHODS

A retrospective analysis was performed on national data obtained from the Australian Institute of Health and Welfare (AIHW) from 1982 to 2013. Changes to the incidence, and the cancer-specific mortality following the diagnosis of ANs were analyzed over this time period, with stratification performed for histological subtype, gender, and age groups (<50y and ≥50y).

RESULTS

Incidence and mortality rates of ANs increased significantly across both genders and age groups. Incidence rates increased by 415%, from 0.40/100 000 population in 1982 to 2.06/100 000 in 2013. Overall mortality rates increased by 130%, from 0.057/100 000 during 1982-1985 to 0.131/100 000 during 2010-2013. Controlling for age group and gender, the incidence rates increased by 20% every four years (Incidence rate ratio (IRR) = 1.20, 95% confidence interval (CI): 1.17, 1.23, global P value<0.0001), and controlling for age, the mortality rates increased by 8% every four years (IRR = 1.08, 95% CI: 1.00, 1.17, global P-value = 0.0401).

CONCLUSION

The increasing use of CT scanning, improvements in pathological assessment of the appendix, and the growing aging population may have contributed in part to the apparent rise in the incidence of ANs.

Antibiotics during childhood and development of appendicitis-a nationwide cohort study

BACKGROUND

Appendicitis is a common disease with a lifespan risk of approximately 8%. The full range of specific causes for the disease remains elusive, but an aberrant microbiota have been identified as a potential risk factor.

AIM

To investigate if use of antibiotics in a paediatric population increases the risk of appendicitis in childhood and adolescence METHODS: We conducted a cohort study from 1 January 1995 to 31 December 2014. A total of 1 385 707 children (0-19 years of age) including 7 406 397 antibiotic prescriptions and 11 861 cases of appendicitis were included. Primary outcome was appendicitis requiring appendectomy according to previous use of antibiotics. Appendicitis and appendectomy were identified from nationwide hospital records, and exposure to antibiotics was identified from nationwide prescription register. Rate ratios (RRs) with 95% confidence intervals were estimated from Poisson and logistic regression models.

RESULTS

Children who received at least one course of antibiotics were at increased risk of developing appendicitis compared to unexposed children (adjusted RR 1.72 [95% confidence interval 1.61-1.85]), mean age of developing appendicitis was 9.8 years (SD 4.1 years). The RR of appendicitis increased by 1.04 (1.04-1.04) per antibiotic course. A higher risk of appendicitis was observed in children exposed to antibiotics within the first 6 months of life (RR 1.46 [1.36-1.56]) and children exposed to broad-spectrum antibiotics (RR 1.33 [1.27-1.39]). After adjustment for number of antibiotic courses, the association between early age of antibiotic exposure and risk of appendicitis and the association between exposure to broad-spectrum antibiotics and the risk of appendicitis both disappeared.

CONCLUSION

Children who receive antibiotics are at increased and dose-dependent risk of appendicitis. The underlying mechanisms merit further investigation.

Appendectomy, Tonsillectomy and Parkinson's Disease Risk: A Swedish Register-Based Study

Introduction: The gut-brain hypothesis proposes that Parkinson's disease (PD) pathology may start in the gut and later spread to the brain in a prion-like manner. As PD pathology is redundant in the appendix and tonsils, which are important gut-associated lymphoid tissues, we examined whether appendectomy and tonsillectomy were associated with later PD risk. Methods: The nested case-control study included 78,650 PD patients born in 1900-1980 and with a diagnosis of PD between 1964 and 2010. For each PD patient, we randomly selected 40 non-PD controls individually matched for sex and year of birth at the date of PD diagnosis. Appendectomy and tonsillectomy before PD diagnosis were ascertained from the Swedish Patient Register from 1964 onward. We calculated odds ratios (OR) with 95% confidence intervals (CI) using conditional logistic regression adjusting for country of birth, highest achieved education, COPD, comorbidity index, and number of hospital visits. Results: Overall, we found 16% lower risk of PD linked to previous appendectomy (OR = 0.84, 95% CI: 0.80-0.88) and 8% lower risk of PD linked to previous tonsillectomy, although not statistically significant (OR = 0.92, 95% CI: 0.81-1.04). A 7 and 15% lower risk of PD was also noted ≥20 years after appendectomy and tonsillectomy, respectively. Similar associations were observed for men and women but were stronger for PD diagnosed after age 60. Conclusion: Appendectomy and potentially also tonsillectomy were associated with a lower risk PD. A potential mechanism may involve surgical removal of alpha-synuclein redundancy in the appendix and tonsils.

Appendectomy, cholecystectomy and diagnostic laparoscopy conducted before pregnancy and risk of adverse birth outcomes: a nationwide registry-based prevalence study 1996-2015

Background

Non-obstetric surgery conducted during pregnancy may increase the risk of adverse birth outcomes like small for gestational age, preterm birth, and miscarriage. Mechanisms are unclear but possibly longer lasting. We examined whether appendectomy, cholecystectomy and diagnostic laparoscopy conducted before pregnancy affect these outcomes.

Methods

This nationwide Danish prevalence study included all pregnancies during 1996–2015 that had an appendectomy, cholecystectomy or diagnostic laparoscopy registered before last menstrual period in the years 1992–2015. We excluded pregnancies with surgery and categorized pre-pregnancy surgery according to timing (0–11, 12–23, and 24+ months before last menstrual period). Outcomes were small for gestational age, late preterm birth (32–37 weeks), early preterm birth (22–31 weeks) and miscarriage (7–21 weeks). We computed absolute risks and used logistic regression comparing pregnancies with surgery 0–11 or 12–23 to 24+ months before last menstrual period, computing odds ratios for each outcome, adjusting for maternal age and smoking.

Results

We identified 15,939 pregnancies with appendectomy, 12,869 pregnancies with cholecystectomy and 19,330 pregnancies with diagnostic laparoscopy. The absolute risk of small for gestational age was 2.2% for patients with appendectomy 0–11 months before last menstrual period, 3.2% 12–23 months before compared with 2.2% when appendectomy was conducted more than 24 months before (adjusted OR 0.95 (95% CI; 0.65 to 1.31) and 1.37(95% CI;1.00 to 1.86). For early preterm birth, the absolute risks were 0.7, 0.5 and 0.8%, for late preterm birth 4.8, 4.4 and 4.7% and for miscarriage 5.7, 6.2 and 5.4%.We observed similar results for cholecystectomy. For diagnostic laparoscopy 0–11 months before pregnancy we found increased risks of small for gestational age (4.0, 2.8 and 2.6%) and late preterm birth (5.9, 5.0 and 4.8%).

Conclusions

We found no increased risk of adverse birth outcomes among pregnancies with appendectomy or cholecystectomy conducted within 2 years before pregnancy compared to more than 2 years before pregnancy. The increased risks 0–11 months after diagnostic laparoscopy are likely explained by confounding by underlying indication. It appears safe to become pregnant any time following appendectomy and cholecystectomy, but, probably depending on indication, attention should be payed 0–11 months after diagnostic laparoscopy.

The Characteristics of Appendicoliths Associated with Acute Appendicitis

Introduction

Differences between appendicoliths associated with appendicitis and those found incidentally have not been studied. The objective of this study was to determine the characteristics of appendicoliths that are associated with acute appendicitis.

Methods

A cross-sectional study of patients with appendicoliths identified on computed tomographic (CT) scan from January 2008 till December 2014 was conducted. Patients were divided into two group: appendicitis and appendicoliths (AA) and incidentally discovered appendicoliths (IA).

Results

Overall, 321 patients were included in the study. Of these, 103 (32%) patients were in the AA group while 218 (68%) patients were in the IA group. Both groups were similar in age and gender distribution. Significantly greater proportion of patients in the AA group had more than one appendicolith [AA vs. IA: 63 (62%) vs. 82 (38%), p < 0.001], appendicolith location at the base [AA vs. IA: 34 (33%) vs. 33 (15%), p < 0.001] and appendicolith diameter of 5 mm or more [AA vs. IA: 71 (69%) vs. 28 (13%), p < 0.001]. On multivariate analysis, more than one appendicolith [Odds ratio (OR): 1.9, 95% CI: 1.1-3.4; p = 0.02] and diameter of 5 mm or more (OR: 13, 95% CI: 7.1-23.6; p < 0.001) were independently associated with acute appendicitis.

Conclusion

Multiple appendicoliths and appendicoliths larger than 5 mm are associated with acute appendicitis.

Seasonal variation of acute appendicitis

Objective:

To determine the seasonal variation of acute appendicitis.

Methods:

A total of 320 patients fulfilling the inclusion criteria were enrolled in the study after getting the written informed consent. Appendectomies were performed by consultant surgeons and residents. After surgery histopathological examination of specimens was performed by consultant Histopathologists at Armed Forces Institute of Pathology Rawalpindi and CMH Peshawar. The patients presenting in different four seasons September to November as autumn, December to February as winter, March to May as spring, June to August as summer, were compared to determine seasonal variations.

Results:

In our study out of all 320 patients 188 (58.75%) were males and 132 (41.25%) were females. Sixty patients (18.75 %) presented in autumn season (Sep-Nov), 52 patients (16.25%) in winter season (Dec-Feb), 78 (24.25%) patients in Spring season (Mar-May).130 (40.62%) patients presented in Summer season (Jun-Aug). There was almost 24.37% increased incidence in summer as compared to winter season, 21.87% increased incidence as compared to autumn season, 16.37% increased incidence as compared to spring season.

Conclusion:

Acute appendicitis incidence is increased in summer months in Pakistan. Preventive measures can be taken during summer season (June to Aug) to decrease morbidity and mortality associated with this disease.

Appendectomy History is not Related to Parkinson's Disease

BACKGROUND

It has been suggested that appendectomy may modify the emergence of Parkinson's disease (PD) by affecting the retrograde transport of α-synuclein (α-syn) from the gastrointestinal system.

OBJECTIVE

To explore the possible role of appendectomy on PD.

METHODS

The retrospective data of the 1625 patients (839 PD, 633 non-α-syn parkinsonism and 153 controls) were compared. Disease specific measures between PD patients with (n = 69) and without (n = 770) appendectomy were also evaluated.

RESULTS

The prevalence of appendectomy was not significantly lower in the PD group (8.2%) compared to the other groups (8.4% and 7.9%, p = 0.98), and the odds of having PD against other diagnoses (OR) were not significantly different in the appendectomy group (OR = 0.99, p = 0.96). No difference was determined between PD patients with and without appendectomy with respect to the age of disease onset, disease duration and severity. Appendectomy-first symptom interval was not determined to be related with PD diagnosis (hazard ratio = 1.12, p = 0.39) and did not predict disease severity in the PD group (OR = 0.99, p = 0.54). Age of appendectomy (lower or higher than 20) also did not affect future PD diagnosis (Relative Risk = 0.9, p = 0.54) or the disease severity.

CONCLUSIONS

The results of the study suggest no effect of appendectomy on the emergence and clinical manifestations of PD. The removal of the appendix is possibly not sufficient to suppress the exposure of the brain stem to α-syn via vagal retrograde transport. Further studies are needed to elucidate the role of appendix in PD.

Familial history aggregation on acute appendicitis

Appendectomy is the most commonly performed surgical procedure, affecting 1%-8% of the paediatric population, with a total 7% lifetime risk, most likely in adolescents and young adults.A case of familial aggregation was reported in our hospital in a family composed of nine siblings from which six of them (66.6%) had been treated of acute appendicitis, five of them in our centre.Many factors have been described as predisposing to appendicitis. Several studies have highlighted the influence of genes in the evolution of this disease and its severity, demonstrating a relative risk increase by three when family history is present.Family history of acute appendicitis is an important factor to be taken into consideration during the medical interview. Clinicians attempting to fine-tune their diagnostic accuracy when patients present with acute abdominal pain should inquire about family history of appendicitis.

Reduced risk of UC in families affected by appendicitis: a Danish national cohort study

OBJECTIVE

The possible aetiological link between appendicitis and UC remains unclear. In order to investigate the hereditary component of the association, we studied the risk of UC in family members of individuals with appendicitis.

DESIGN

A cohort of 7.1 million individuals was established by linkage of national registers in Denmark with data on kinship and diagnoses of appendicitis and UC. Poisson regression models were used to calculate first hospital contact rate ratios (RR) for UC with 95% CIs between individuals with or without relatives with a history of appendicitis.

RESULTS

During 174 million person-years of follow-up between 1977 and 2011, a total of 190 004 cohort members developed appendicitis and 45 202 developed UC. Individuals having a first-degree relative with appendicitis before age 20 years had significantly reduced risk of UC (RR 0.90; 95% CI 0.86 to 0.95); this association was stronger in individuals with a family predisposition to UC (RR 0.66; 95% CI 0.51 to 0.83).

CONCLUSIONS

Individuals with a first-degree relative diagnosed with appendicitis before age 20 years are at reduced risk of UC, particularly when there is a family predisposition to UC. Our findings question a previously hypothesised direct protective influence of appendicitis on inflammation of the large bowel. Rather, genetic or environmental factors linked to an increased risk of appendicitis while being protective against UC may explain the repeatedly reported reduced relative risk of UC in individuals with a history of appendicitis.

Appendectomy in mid and later life and risk of Parkinson's disease: A population-based study

INTRODUCTION

Pathogenic movement of alpha-synuclein from the gut to the brain in PD has been proposed. The appendix has a relatively high density of alpha-synuclein deposition in neurologically healthy individuals. We investigated the incidence of PD after appendectomy.

METHODS

Using cause-specific hazards regression models, we compared persons over 35 years of age who had undergone appendectomy with two groups of age- and sex-matched individuals having had: (1) a cholecystectomy and (2) neither procedure. Subsequent diagnoses of PD were identified.

RESULTS

Among 42,999 individuals undergoing appendectomy, no difference in risk of PD was identified compared to cholecystectomy (hazard ratio = 1.004; 95% confidence interval: 0.740-1.364). Compared with no procedure, individuals with appendectomy had a higher incidence of PD within 5 years, but no significant difference in risk thereafter.

CONCLUSION

In our study, appendectomy in mid or late life does not appear to be associated with a reduced risk of PD. © 2016 International Parkinson and Movement Disorder Society.

Changing relationships between smoking and psychiatric disorders across twentieth century birth cohorts: clinical and research implications

As the risks of tobacco use become recognized and smoking becomes stigmatized, new smokers may be increasingly driven to smoke by biological or genetic vulnerabilities rather than social desirability. Given that genetic risk for deviant proneness is shared across other psychiatric and addictive disorders, we predicted that as rates of smoking decreased through the latter half of the twentieth century, associations between smoking and psychopathology would increase. Participants (N=25 412) from a large US study-the National Epidemiologic Survey on Alcohol and Related Conditions, NESARC-were interviewed using the Alcohol Use Disorder and Associated Disabilities Interview Schedule - DSM-IV Version (AUDADIS-IV) and classified into one of five birth cohort decades (1940s to 1980s) and three smoking history (nonsmokers, never-dependent smokers and ever-dependent smokers) groups. We found that the prevalence of smoking decreased across the five birth cohorts, but associations of smoking with drug and AUDs, attention-deficit hyperactivity disorder, bipolar disorder and antisocial personality disorder, each increased monotonically in more recently born cohorts, even after adjusting for concurrent demographic and socioeconomic changes. For drug and AUDs, increases were observed among smokers both with and without a history of nicotine dependence; for other outcomes, increases were entirely driven by nicotine-dependent smokers. Findings suggest that smokers in more recent cohorts have disproportionately high psychiatric vulnerability, and may benefit from greater mental health screenings. Differentiating between casual and dependent smokers may further help prioritize those at greatest risk. Researchers should also be aware of potential variation in psychiatric comorbidity based on cohort of birth when defining groups of smokers, to minimize confounding.

Decreased stress resilience in young men significantly increases the risk of subsequent peptic ulcer disease - a prospective study of 233 093 men in Sweden

BACKGROUND

Psychosocial stress may influence peptic ulcer disease (PUD) risk, but it can be difficult to identify reliably whether stressful exposures pre-dated disease. The association of stress resilience (susceptibility to stress) with subsequent PUD risk has been incompletely investigated.

AIM

To assess if stress resilience in adolescence is associated with subsequent PUD risk.

METHODS

The participants comprised of 233 093 men resident in Sweden, born 1952-1956 and assessed for compulsory military conscription during 1969-1976, with data provided by national Swedish registers. Stress resilience was evaluated through semi-structured interviews by a certified psychologist. Cox regression assessed the association between stress resilience in adolescence and the risk of PUD from 1985 to 2009, between ages 28 and 57 years, with adjustment for parental socioeconomic index, household crowding and number of siblings in childhood, as well as cognitive function and erythrocyte sedimentation rate in adolescence.

RESULTS

In total, 2259 first PUD diagnoses were identified. Lower stress resilience in adolescence is associated with a higher risk of PUD in subsequent adulthood: compared with high resilience, the adjusted hazard ratios (and 95% CI) are 1.84 (1.61-2.10) and 1.23 (1.09-1.38) for low and moderate stress resilience, respectively.

CONCLUSION

Stress may be implicated in the aetiology of PUD and low stress resilience is a marker of risk.

Risk of acute appendicitis in and around pregnancy: a population-based cohort study from England

OBJECTIVE

To determine the absolute and relative risk of acute appendicitis during the antepartum and postpartum periods compared with the time outside pregnancy among women of childbearing age.

BACKGROUND

Acute appendicitis is the most common nonobstetric surgical emergency during pregnancy. Estimates of the incidence of acute appendicitis in pregnancy remain imprecise and inconsistent.

METHODS

All potential fertile women aged 15 to 44 years registered within Clinical Practice Research Datalink with linkages to the Hospital Episodes Statistics between 1997 and 2012 were identified. Absolute rates of acute appendicitis were calculated during the antepartum and postpartum periods and were compared with the time outside pregnancy in terms of incidence rate ratio (IRR) using a Poisson regression model.

RESULTS

Among 1,624,804 women, there were 362,219 pregnancies resulting in live or stillbirths. Compared with the time outside pregnancy, the rate of acute appendicitis was 35% lower during the antepartum period [IRR, 0.65; 95% confidence interval (CI), 0.55-0.76], with the lowest rate reported during the third trimester (IRR, 0.47; 95% CI, 0.35-0.64) for all ages; no increased risk of acute appendicitis was observed in the postpartum period compared with the time outside pregnancy among women aged 15 to 34 years but an 84% increased risk for women older than 35 years (IRR, 1.84; 95% CI, 1.18-2.86). The highest and lowest rates of negative appendectomy were encountered in the second and the third trimesters, respectively.

CONCLUSIONS

Pregnant women are less likely to be diagnosed with acute appendicitis than nonpregnant women, with the lowest risk reported during the third trimester.

Gastrointestinal tract-derived pulse granulomata: clues to an underrecognized pseudotumor

Pulse granulomata (PG) in the lung and oral pathology literature are presumed due to food (pulse) introduced by mucosal injury. Herein, we report the largest series of PG in the gastrointestinal tract (GIT): 22 resections were prospectively collected from 17 patients (8 men, range=28 to 85 y). All patients had a history of intestinal injury/disease: diverticulitis, fistula, adenocarcinoma, perforation, ulcerative colitis, appendicitis, anastomotic site leak, and/or stent leak. Nine of 22 specimens were designated "masses"; most of these were clinically concerning for neoplasia. Sites of involvement included the small and large intestine, appendix, liver, gallbladder, mesentery, omentum, peritoneum, cervix, ovary, and skin. PG were typically nodular (21/22) and multifocal (15/22); most involved the external surface of the bowel (20/22), and they ranged in size from 1.5 to 100 mm. Histologically, they contained variable amounts of hyaline ribbons and rings, inflammation, foreign body giant cells, calcifications, and food; larger lesions displayed circumferential stellate fibrosis (12/22). We describe 3 morphologic variants: hyaline predominant (mimicking amyloid), cellular predominant (mimicking spindle cell neoplasms), and sclerosing mesenteritis-like. All patients are alive and well at the time of follow-up. Histologically processed legumes showed similar structures as those identified in PG, providing support for an entrapped food origin. In summary, we detail important clinicopathologic clues, describe the PG morphologic spectrum, and demonstrate how to distinguish PG from their mimics. Although PG can present as clinically concerning masses, we conclude that they are pseudotumors arising secondary to entrapped food introduced through mucosal trauma, similar to their lung and oral counterparts.

Seasonal variations of acute appendicitis and nonspecific abdominal pain in Finland

AIM: To investigate whether seasonal changes had an effect on the incidence of acute appendicitis (AA) or nonspecific abdominal pain (NSAP).

METHODS: We carried out a national register study of all patients with a hospital discharge diagnosis of AA and acute NSAP in Finland. Data were analyzed for the whole country and correlated to seasonal and weather parameters (temperature, humidity). Moreover, additional sub-analyses were performed for five geographically different area of Finland.

RESULTS: The observation period spanned 21 years, with 186558 appendectomies, of which 137528 (74%) cases were reported as AA. The incidence of AA declined for 32% over the study period. The average incidence of the NSAP was 34/10000 per year. The mean annual temperature, but not relative humidity, showed clear geographical variations. The incidence of AA decreased significantly during the cold months of the year. No correlation was detected between temperature and incidence of NSAP. Humidity had a statistically significant impact on NSAP.

CONCLUSION: The incidence of acute appendicitis is declining in Finland. We detected a clear seasonality in the incidence of AA and NSAP.

Genetic and environmental influences on the risk of acute appendicitis in twins

BACKGROUND

Acute appendicitis is common but the aetiology is unclear. This study examined the heritability of acute appendicitis.

METHODS

The study included twin pairs with known zygosity born between 1959 and 1985. Individuals with acute appendicitis were found by record linkage with the Swedish Inpatient Register. Comparing monodizygotic and dizygotic twins, the similarity and relative proportions of phenotypic variance resulting from genetic and environmental factors were analysed. Risks of acute appendicitis explained by heritability and environmental effects were estimated.

RESULTS

Some 3441 monozygotic and 2429 dizygotic twins were identified. Almost no genetic effects were found in males (8 (95 per cent confidence interval 0 to 50) per cent), but shared (31 (0 to 49) per cent) and non-shared (61 (47 to 74) per cent) environmental factors accounted for this risk. In females, the heritability was estimated as 20 (0 to 36) per cent and the remaining variation was due to non-shared environmental factors (80 (64 to 98) per cent). For the sexes combined, genetic effects accounted for 30 (5 to 40) per cent and non-shared environmental effects for 70 (60 to 81) per cent of the risk.

CONCLUSION

Acute appendicitis has a complex aetiology with sex differences in heritability and environmental factors.

Heritability and linkage analysis of appendicitis utilizing age at onset

Appendicitis usually afflicts the young, but there is a large tail in the distribution of onset age. The genetics of this disease are still not well understood. A heritability analysis and genome wide linkage analysis of a large twin dataset was undertaken. Treating age of onset of appendicitis as a censored survival trait revealed a heritability of 0.21, and found evidence of linkage to Chromosome 1p37.3.