Risks of deep vein thrombosis, pulmonary embolism, and bleeding after covid-19: nationwide self-controlled cases series and matched cohort study

OBJECTIVE

To quantify the risk of deep vein thrombosis, pulmonary embolism, and bleeding after covid-19.

DESIGN

Self-controlled case series and matched cohort study.

SETTING

National registries in Sweden.

PARTICIPANTS

1 057 174 people who tested positive for SARS-CoV-2 between 1 February 2020 and 25 May 2021 in Sweden, matched on age, sex, and county of residence to 4 076 342 control participants.

MAIN OUTCOMES MEASURES

Self-controlled case series and conditional Poisson regression were used to determine the incidence rate ratio and risk ratio with corresponding 95% confidence intervals for a first deep vein thrombosis, pulmonary embolism, or bleeding event. In the self-controlled case series, the incidence rate ratios for first time outcomes after covid-19 were determined using set time intervals and the spline model. The risk ratios for first time and all events were determined during days 1-30 after covid-19 or index date using the matched cohort study, and adjusting for potential confounders (comorbidities, cancer, surgery, long term anticoagulation treatment, previous venous thromboembolism, or previous bleeding event).

RESULTS

Compared with the control period, incidence rate ratios were significantly increased 70 days after covid-19 for deep vein thrombosis, 110 days for pulmonary embolism, and 60 days for bleeding. In particular, incidence rate ratios for a first pulmonary embolism were 36.17 (95% confidence interval 31.55 to 41.47) during the first week after covid-19 and 46.40 (40.61 to 53.02) during the second week. Incidence rate ratios during days 1-30 after covid-19 were 5.90 (5.12 to 6.80) for deep vein thrombosis, 31.59 (27.99 to 35.63) for pulmonary embolism, and 2.48 (2.30 to 2.68) for bleeding. Similarly, the risk ratios during days 1-30 after covid-19 were 4.98 (4.96 to 5.01) for deep vein thrombosis, 33.05 (32.8 to 33.3) for pulmonary embolism, and 1.88 (1.71 to 2.07) for bleeding, after adjusting for the effect of potential confounders. The rate ratios were highest in patients with critical covid-19 and highest during the first pandemic wave in Sweden compared with the second and third waves. In the same period, the absolute risk among patients with covid-19 was 0.039% (401 events) for deep vein thrombosis, 0.17% (1761 events) for pulmonary embolism, and 0.101% (1002 events) for bleeding.

CONCLUSIONS

The findings of this study suggest that covid-19 is a risk factor for deep vein thrombosis, pulmonary embolism, and bleeding. These results could impact recommendations on diagnostic and prophylactic strategies against venous thromboembolism after covid-19.

The relationship between disability and parental status: a register study of the 1968 to 1970 birth cohorts

BACKGROUND

Having children is a major life course event yet some disabilities could make it biologically challenging and some others could limit access to necessary socioeconomic resources. To date, there is relatively little data on disability and parental status and our study aimed to investigate this relationship.

METHODS

This longitudinal cohort study was based on register data obtained from all people born in Sweden from 1968 to 1970 (n = 440220). We performed descriptive analyses, graphical plots, logistic regression, and Cox regression analyses.

RESULTS

Our findings from both logistic regression and Cox regression indicated that individuals that started to receive disability benefits at an early age had reduced chances of having children during the follow-up duration. Men with disabilities were less likely to have children when compared to women with disabilities and to men and women without disabilities.

CONCLUSIONS

We found evidence that disability during early adulthood was associated with reduced chances of having children. Findings support policies and programmes aimed at promoting optimal health during early adulthood, as this would promote continued labour force participation, reduce early use of disability benefits, and possibly improve chances of becoming a parent.

Effect of extreme hot and cold weather on cause-specific hospitalizations in Sweden: A time series analysis

Considering that several meteorological variables can contribute to weather vulnerability, the estimation of their synergetic effects on health is particularly useful. The spatial synoptic classification (SSC) has been used in biometeorological applications to estimate the effect of the entire suite of weather conditions on human morbidity and mortality. In this study, we assessed the relationships between extremely hot and dry (dry tropical plus, DT+) and hot and moist (moist tropical plus, MT+) weather types in summer and extremely cold and dry (dry polar plus, DP+) and cold and moist (moist polar, MP+) weather types in winter and cardiovascular and respiratory hospitalizations by age and sex. Time-series quasi-Poisson regression with distributed lags was used to assess the relationship between oppressive weather types and daily hospitalizations over 14 subsequent days in the extended summer (May to August) and 28 subsequent days during the extended winter (November to March) over 24 years in 4 Swedish locations from 1991 to 2014. In summer, exposure to hot weather types appeared to reduce cardiovascular hospitalizations while increased the risk of hospitalizations for respiratory diseases, mainly related to MT+. In winter, the effect of cold weather on both cause-specific hospitalizations was small; however, MP+ was related to a delayed increase in cardiovascular hospitalizations, whilst MP+ and DP + increased the risk of hospitalizations due to respiratory diseases. This study provides useful information for the staff of hospitals and elderly care centers who can help to implement protective measures for patients and residents. Also, our results could be helpful for vulnerable people who can adopt protective measures to reduce health risks.

Hot and cold weather based on the spatial synoptic classification and cause-specific mortality in Sweden: a time-stratified case-crossover study

The spatial synoptic classification (SSC) is a holistic categorical assessment of the daily weather conditions at specific locations; it is a useful tool for assessing weather effects on health. In this study, we assessed (a) the effect of hot weather types and the duration of heat events on cardiovascular and respiratory mortality in summer and (b) the effect of cold weather types and the duration of cold events on cardiovascular and respiratory mortality in winter. A time-stratified case-crossover design combined with a distributed lag nonlinear model was carried out to investigate the association of weather types with cause-specific mortality in two southern (Skåne and Stockholm) and two northern (Jämtland and Västerbotten) locations in Sweden. During summer, in the southern locations, the Moist Tropical (MT) and Dry Tropical (DT) weather types increased cardiovascular and respiratory mortality at shorter lags; both hot weather types substantially increased respiratory mortality mainly in Skåne. The impact of heat events on mortality by cardiovascular and respiratory diseases was more important in the southern than in the northern locations at lag 0. The cumulative effect of MT, DT and heat events lagged over 14 days was particularly high for respiratory mortality in all locations except in Jämtland, though these did not show a clear effect on cardiovascular mortality. During winter, the dry polar and moist polar weather types and cold events showed a negligible effect on cardiovascular and respiratory mortality. This study provides valuable information about the relationship between hot oppressive weather types with cause-specific mortality; however, the cold weather types may not capture sufficiently effects on cause-specific mortality in this sub-Arctic region.

Adverse perinatal conditions and receiving a disability pension early in life

OBJECTIVE

The number of young adults on disability pension (DP) is increasing in European countries, creating a need to understand the related risk factors. This study aimed to determine whether adverse perinatal conditions are associated with receiving a DP early in life.

METHODS

This longitudinal cohort study consisted of all persons (N = 453,223) born in Sweden during 1973-1977, observed from 1991 through 2010 when they were aged between 16 and 37 years. Statistics Sweden provided linked national data on the children and their parents. We used logistic regression to assess the association between perinatal health conditions (birth defect, Apgar score, and small for gestational age) and receiving a DP, adjusting for maternal education and the sex of the child.

RESULTS

New recipients of DP were significantly more likely to have had a birth defect (adjusted odds ratio [AOR] 2.74, 95% CI: 2.49-3.00), to have had low Apgar score (AOR 2.12, 95% CI: 1.77-2.52), to have been small for gestational age (AOR 1.73, 95% CI: 1.54-1.94) and to be females (AOR 1.55, 95% CI: 1.46-1.64). Higher maternal education was associated with lower odds of receiving a DP (AOR 0.74, 95% CI: 0.69-0.79) for those with high school education and (AOR 0.67, 95% CI: 0.59-0.75) for those with university education. Age-stratified analysis confirmed increased odds of receiving a DP among those with birth defects and small for gestational age, but this effect reduced with increasing age. Apgar score was significantly associated with starting to receive a DP at ages 16-18 and 19-29, but not at ages 30-33. Women had lower odds of receiving a DP at ages 16-18 (AOR 0.73, 95% CI: 0.64-0.85); however, this reversed from age 19 and upwards (AOR 1.53, 95% CI: 1.41-1.67) and (AOR 2.16, 95% CI: 1.95-2.40) for the age groups of 19-29 and 30-33, respectively. Persons with high maternal education were less likely to receive a DP regardless of age at receiving a DP.

CONCLUSION

Having a birth defect was the strongest indicator of receiving a DP during early adulthood, followed by small for gestational age and low Apgar score. Overall, the effects of the studied perinatal health conditions were pronounced in those who received a DP at 16-18 years, but this effect weakened with increasing age at receiving a DP. Our findings suggest that policies and programs geared at promoting optimal health at birth might contribute to a reduction in receiving a DP.

Season of birth, stillbirths, and neonatal mortality in Sweden: the Sami and non-Sami population, 1800-1899

Seasonal patterns of neonatal mortality and stillbirths have been found around the world. However, little is known about the association between season of birth and infant mortality of pre-industrial societies in a subarctic environment. In this study, we compared how season of birth affected the neonatal and stillbirth risk among the Sami and non-Sami in Swedish Sápmi during the nineteenth century. Using digitised parish records from the Demographic Data Base at Umeå University, we applied logistic regression models for estimating the association of season of birth with stillbirths and neonatal mortality, respectively. Higher neonatal mortality was found among the winter- and autumn-born Sami, compared to summer-born infants. Stillbirth risk was higher during autumn compared to summer among the Sami, whereas we found no seasonal differences in mortality among the non-Sami population. We relate the higher neonatal mortality risk among winter-born Sami to differences in seasonality of living conditions associated with reindeer herding.

Weather extremes and perinatal mortality - Seasonal and ethnic differences in northern Sweden, 1800-1895

BACKGROUND

Many studies have shown the impact of heat and cold on total and age-specific mortality, but knowledge gaps remain regarding weather vulnerability of very young infants. This study assessed the association of temperature extremes with perinatal mortality (stillbirths and deaths in the first week of life), among two ethnic groups in pre-industrial northern Sweden.

METHODS

We used population data of indigenous Sami and non-Sami in selected parishes of northern Sweden, 1800-1895, and monthly temperature data. Multiple logistic regression models were conducted to estimate the association of cold (<10th percentile of temperature) and warmth (>90th percentile) in the month of birth with perinatal mortality, adjusted for cold and warmth in the month prior birth and period, stratified by season and ethnicity.

RESULTS

Perinatal mortality was slightly higher in Sami than in non-Sami (46 vs. 42 / 1000 live and stillbirths), but showed large variations across the region and over time. Both groups saw the highest perinatal mortality in autumn. For Sami, winter was a high-risk time as well, while for non-Sami, seasonality was less distinct. We found an association between exposure to cold and perinatal mortality among winter-born Sami [Odds ratio (OR) 1.91, 95% confidence interval (CI) 1.26-2.92, compared to moderate temperature], while there was little effect of cold or warmth during other seasons. Non-Sami, meanwhile, were affected in summer by warmth (OR 0.20, CI 0.05-0.81), and in autumn by cold (OR 0.39, CI 0.19-0.82).

CONCLUSIONS

In this pre-industrial, subarctic setting, the indigenous Sami's perinatal mortality was influenced by extreme cold in winter, while non-Sami seemed to benefit from high temperature in summer and low temperature in autumn. Climate vulnerability of these two ethnic groups sharing the same environment was shaped by their specific lifestyles and living conditions.

First a job, and then a family? Impacts of disabilities on young people's life courses in a nineteenth-century Swedish region

This study considers the life courses of young men and women with and without disabilities in the Sundsvall region of Sweden during the nineteenth century. It aims to ascertain how disability and gender shaped their involvement in work and their experience of family in order to assess the extent of their social inclusion. Through the use of Swedish parish registers digitized by the Demographic Data Base, Umeå University, we examine 8,874 individuals observed from 15 to 33 years of age to investigate whether obtaining a job, getting married and having children were less frequent events for people with disabilities. Our results reveal that this was the case and particularly for those with mental disabilities, even if having an impairment did not wholly prevent people from finding a job. However, their work did not represent the key to family formation and for the women it implied a higher rate of illegitimacy. We argue that the lower level of inclusion in work and family was not solely the outcome of the impairment itself, but differed in relation to the particular attitudes towards men and women with disabilities within the labour market and society more generally in this particular context.

Do unequal societies cause death among the elderly? A study of the health effects of inequality in Swedish municipalities in 2006

BACKGROUND

A lively public and academic debate has highlighted the potential health risks of living in regions characterized by inequality. Research provides an ambiguous picture, however, with positive association between income equality and health mainly being found on higher levels of geographical division, such as nations, but rarely at local level.

METHODS

We examined the association between income inequality (using the Gini coefficient) and all-cause mortality in Swedish municipalities in the 65-74 age group. A multi-level analysis was applied and controlled for by variables including individual income and average income level in the municipality. The analyses were based on individual register data on all residents born between 1932 and 1941, outcomes were measured for the year 2006.

RESULTS

Lower individual income and lower average income in the municipality of residence were associated with significantly increased mortality. We found an association between income inequality and mortality with excessive deaths in unequal municipalities after controlling for mean income level and personal income. The results from the analysis of individual data differed substantially from the analysis of aggregate data.

CONCLUSIONS

Income inequality was significantly associated with mortality in the age group 65-74 at municipality level. The association is small compared to many other variables, but is not negligible. Even in a comparatively equal society like Sweden, the potential effects of income inequality on mortality at the local level warrant consideration.

The effect of Rh-negative disease on perinatal mortality: some evidence from the Skellefteå region, Sweden, 1860-1900

The Rh-negative gene is a well-known cause of perinatal mortality. In this article, we analyze the possible role of Rh disease in perinatal mortality and stillbirths in a particular historical setting: the Skellefteå region in northern Sweden between 1860 and 1900. The data used for the study cover 23,067 children born to 4,943 women. The exact impact is not possible to establish using historical data, but the typical pattern of the disease allows us to make estimations. The expected levels based on knowledge of blood group distribution, the risk of sensitization from Rh incompatability, and the risk of perinatal mortality in births by sensitized mothers are compared with the observed levels. The results show that Rh disease was important for perinatal mortality and clustering of deaths within families.