Lessons learned about prevalence and growth rates of abdominal aortic aneurysms from a 25-year ultrasound population screening programme.

BACKGROUND: This study aimed to assess how the prevalence and growth rates of small and medium abdominal aortic aneurysms (AAAs) (3·0-5·4 cm) have changed over time in men aged 65 years, and to evaluate long-term outcomes in men whose aortic diameter is 2·6-2·9 cm (subaneurysmal), and below the standard threshold for most surveillance programmes. METHODS: The Gloucestershire Aneurysm Screening Programme (GASP) started in 1990. Men aged 65 years with an aortic diameter of 2·6-5·4 cm, measured by ultrasonography using the inner to inner wall method, were included in surveillance. Aortic diameter growth rates were estimated separately for men who initially had a subaneurysmal aorta, and those who had a small or medium AAA, using mixed-effects models. RESULTS: Since 1990, 81 150 men had ultrasound screening for AAA (uptake 80·7 per cent), of whom 2795 had an aortic diameter of 2·6-5·4 cm. The prevalence of screen-detected AAA of 3·0 cm or larger decreased from 5·0 per cent in 1991 to 1·3 per cent in 2015. There was no evidence of a change in AAA growth rates during this time. Of men who initially had a subaneurysmal aorta, 57·6 (95 per cent c.i. 54·4 to 60·7) per cent were estimated to develop an AAA of 3·0 cm or larger within 5 years of the initial scan, and 28·0 (24·2 to 31·8) per cent to develop a large AAA (at least 5·5 cm) within 15 years. CONCLUSION: The prevalence of screen-detected small and medium AAAs has decreased over the past 25 years, but growth rates have remained similar. Men with a subaneurysmal aorta at age 65 years have a substantial risk of developing a large AAA by the age of 80 years.

Previous miscarriage and the subsequent risk of preterm birth in Scotland, 1980-2008: a historical cohort study.

OBJECTIVE: To determine whether the relationship between previous miscarriage and risk of preterm birth changed over the period 1980-2008, and to determine whether the pattern varied according to the cause of the preterm birth. DESIGN: Linked birth databases. SETTING: All Scottish NHS hospitals. POPULATION: A total of 732 719 nulliparous women with a first live birth between 1980 and 2008. METHODS: Risk was estimated using logistic regression. MAIN OUTCOME MEASURES: Preterm birth, subdivided by cause (spontaneous, induced with a diagnosis of pre-eclampsia, or induced without a diagnosis of pre-eclampsia) and severity [extreme (24-28 weeks of gestation), moderate (29-32 weeks of gestation), and mild (33-36 weeks of gestation)]. RESULTS: Consistent with previous studies, previous miscarriage was associated with an increased risk of all-cause preterm birth (adjusted odds ratio, aOR 1.26; 95% confidence interval, 95% CI 1.22-1.29). This arose from associations with all subtypes. The strongest association was found with extreme preterm birth (aOR 1.73; 95% CI 1.57-1.90). Risk increased with the number of miscarriages. Women with three or more miscarriages had the greatest risk of all-cause preterm birth (aOR 2.14; 95% CI 1.93-2.38), and the strongest association was with extreme preterm birth (aOR 3.87; 95% CI 2.85-5.26). The strength of the association between miscarriage and preterm birth decreased from 1980 to 2008. This was because of weakening associations with spontaneous preterm birth and induced preterm birth without a diagnosis of pre-eclampsia. CONCLUSIONS: The association between a prior history of miscarriage and the risk of preterm birth declined in Scotland over the period 1980-2008. We speculate that changes in the methods of managing incomplete termination of pregnancy might explain the trend, through reduced cervical damage.

Previous caesarean delivery and the risk of unexplained stillbirth: retrospective cohort study and meta-analysis.

OBJECTIVE: To determine whether caesarean delivery in the first pregnancy is a risk factor for unexplained antepartum stillbirth in a second pregnancy. DESIGN: A population-based retrospective cohort study and meta-analysis. SETTING: All maternity units in Scotland. PARTICIPANTS: A cohort of 128 585 second births, 1999-2008. METHODS: Time-to-event analysis and random-effects meta-analysis. MAIN OUTCOME MEASURE: Risk of unexplained antepartum stillbirth in a second pregnancy. RESULTS: There were 88 stillbirths among 23 688 women with a previous caesarean delivery (2.34 per 10 000 women per week) and 288 stillbirths in 104 897 women who had previously delivered vaginally (1.67 per 10 000 women per week, P = 0.002). When analysed by cause, women with a previous caesarean delivery had an increased risk of unexplained stillbirth (hazard ratio, HR 1.47; 95% confidence interval, 95% CI 1.12-1.94; P = 0.006) and, as previously observed, the excess risk was apparent from 34 weeks of gestation onwards. The risk did not differ in relation to the indication of the caesarean delivery, and was independent of maternal characteristics and previous obstetric complications. We identified three other comparable studies (two in North America and one in Europe), and meta-analysis of these studies showed a statistically significant association between previous caesarean delivery and the risk of antepartum stillbirth in the second pregnancy (pooled HR 1.40; 95% CI 1.10-1.77; P = 0.006). CONCLUSIONS: Women who have had a previous caesarean delivery are at increased risk of unexplained stillbirth in the second pregnancy. TWEETABLE ABSTRACT: Caesarean first delivery is associated with an increased risk of unexplained stillbirth in the next pregnancy.

Cadmium body burden and increased blood pressure in middle-aged American Indians: the Strong Heart Study.

Cadmium (Cd) is an environmental pollutant that has been associated with cardiovascular disease in populations, but the relationship of Cd with hypertension has been inconsistent. We studied the association between urinary Cd concentrations, a measure of total body burden, and blood pressure in American Indians, a US population with above national average Cd burden. Urinary Cd was measured using inductively coupled plasma mass spectrometry, and adjusted for urinary creatinine concentration. Among 3714 middle-aged American Indian participants of the Strong Heart Study (mean age 56 years, 41% male, 67% ever-smokers, 23% taking antihypertensive medications), urinary Cd ranged from 0.01 to 78.48 µg g-1 creatinine (geometric mean=0.94 µg g-1) and it was correlated with smoking pack-year among ever-smokers (r2=0.16, P<0.0001). Participants who were smokers were on average light-smokers (mean 10.8 pack-years), and urinary Cd was similarly elevated in light- and never-smokers (geometric means of 0.88 µg g-1 creatinine for both categories). Log-transformed urinary Cd was significantly associated with higher systolic blood pressure in models adjusted for age, sex, geographic area, body mass index, smoking (ever vs never, and cumulative pack-years) and kidney function (mean blood pressure difference by lnCd concentration (ß)=1.64, P=0.002). These associations were present among light- and never-smokers (ß=2.03, P=0.002, n=2627), although not significant among never-smokers (ß=1.22, P=0.18, n=1260). Cd was also associated with diastolic blood pressure among light- and never-smokers (ß=0.94, P=0.004). These findings suggest that there is a relationship between Cd body burden and increased blood pressure in American Indians, a population with increased cardiovascular disease risk.