Overweight in midlife and risk of cancer in late life: A nationwide Swedish twin study

Global burden of gynaecological cancers in 2022 and projections to 2050

Background

The incidence and mortality of gynaecological cancers can significantly impact women's quality of life and increase the health care burden for organisations globally. The objective of this study was to evaluate global inequalities in the incidence and mortality of gynaecological cancers in 2022, based on The Global Cancer Observatory (GLOBOCAN) 2022 estimates. The future burden of gynaecological cancers (GCs) in 2050 was also projected.

Methods

Data regarding to the total cases and deaths related to gynaecological cancer, as well as cases and deaths pertaining to different subtypes of GCs, gathered from the GLOBOCAN database for the year 2022. Predictions for the number of cases and deaths in the year 2050 were derived from global demographic projections, categorised by world region and Human Development Index (HDI).

Results

In 2022, there were 1 473 427 new cases of GCs and 680 372 deaths. The incidence of gynecological cancer reached 30.3 per 100 000, and the mortality rate hit 13.2 per 100 000. The age-standardised incidence of GCs in Eastern Africa is higher than 50 per 100 000, whereas the age-standardised incidence in Northern Africa is 17.1 per 100 000. The highest mortality rates were found in East Africa (ASMR (age-standardised mortality rates) of 35.3 per 100 000) and the lowest in Australia and New Zealand (ASMR of 8.1 per 100 000). These are related to the endemic areas of HIV and HPV. Very High HDI countries had the highest incidence of GCs, with ASIR (age-standardised incidence rates) of 34.8 per 100 000, and low HDI countries had the second highest incidence rate, with an ASIR of 33.0 per 100 000. Eswatini had the highest incidence and mortality (105.4 per 100 000; 71.1 per 100 000) and Yemen the lowest (5.8 per 100 000; 4.4 per 100 000). If the current trends in morbidity and mortality are maintained, number of new cases and deaths from female reproductive tract tumours is projected to increase over the next two decades.

Conclusions

In 2022, gynaecological cancers accounted for 1 473 427 new cases and 680 372 deaths globally, with significant regional disparities in incidence and mortality rates. The highest rates were observed in Eastern Africa and countries with very high and low HDI, with Eswatini recording the most severe statistics. If current trends continue, the number of new cases and deaths from gynaecological cancers is expected to rise over the next two decades, highlighting the urgent need for effective interventions.

Overweight and risk of type 2 diabetes: A prospective Chinese twin study

OBJECTIVES

This study aimed to estimate the association between overweight and type 2 diabetes mellitus (T2DM) in twins, and further to explore whether genetic and early-life environmental factors account for this association.

METHODS

This study included 31,197 twin individuals from the Chinese National Twin Registry (CNTR). Generalized estimating equation (GEE) models were applied for unmatched case-control analysis. Conditional logistic regressions were used in co-twin matched case-control analysis. Logistic regressions were fitted to examine the differences in odds ratios (ORs) from the GEE models and conditional logistic regressions. Bivariate genetic model was used to explore the genetic and environmental correlation between body mass index (BMI) and T2DM.

RESULTS

In the GEE model, overweight was associated with a higher T2DM risk (OR=2.71, 95% confidence interval (CI): 1.96∼3.73), compared with participants with normal BMI. In the multi-adjusted conditional logistic regression, the association was still significant (OR=2.60, 95% CI: 1.15∼5.87). The ORs from the unmatched and matched analyses were different (P = 0.042). Particularly, overweight could increase T2DM risk in monozygotic (MZ) twins, and the difference in ORs between the unmatched and matched designs was significant (P = 0.014). After controlling for age and sex, the positive BMI-T2DM association was partly due to a significant genetic correlation (rA= 0.31, 95% CI: 0.20∼0.41).

CONCLUSIONS

Our findings suggest that genetics and early-life environments might account for the observed overweight-T2DM association. Genetic correlation between BMI and T2DM further provides evidence for the influence of overlap genes on their association.

Association of low birth weight with cardiometabolic diseases in Swedish twins: a population-based cohort study

OBJECTIVES

To examine the association between low birth weight (LBW) and cardiometabolic diseases (CMDs, including heart disease, stroke and type 2 diabetes mellitus) in adulthood, and to explore whether genetic, early-life environmental and healthy lifestyle factors play a role in this association.

DESIGN

A population-based twin study.

SETTING

Twins from the Swedish Twin Registry who were born in 1958 or earlier participated in the Screening Across the Lifespan Twin (SALT) study for a full-scale screening during 1998-2002 and were followed up until 2014.

PARTICIPANTS

19 779 twin individuals in Sweden with birthweight data available (mean age: 55.45 years).

PRIMARY AND SECONDARY OUTCOME MEASURES

CMDs were assessed based on self-reported medical records, medication use and records from the National Patient Registry. A lifestyle index encompassing smoking status, alcohol consumption, exercise levels and Body Mass Index was derived from the SALT survey and categorised as unfavourable, intermediate or favourable. Data were analysed using generalised estimating equation (GEE) models and conditional logistic regression models.

RESULTS

Of all participants, 3998 (20.2%) had LBW and 5335 (27.0%) had incident CMDs (mean age at onset: 63.64±13.26 years). In GEE models, the OR of any CMD was 1.39 (95% CI 1.27 to 1.52) for LBW. In conditional logistic regression models, the LBW-CMD association became non-significant (OR=1.21, 95% CI 0.94 to 1.56). The difference in ORs from the two models was statistically significant (p<0.001). In the joint effect analysis, the multiadjusted OR of CMDs was 3.47 (95% CI 2.72 to 4.43) for participants with LBW plus an unfavourable lifestyle and 1.25 (95% CI 0.96 to 1.62) for those with LBW plus a favourable lifestyle.

CONCLUSION

LBW is associated with an increased risk of adult CMDs, and genetic and early-life environmental factors may account for this association. However, a favourable lifestyle profile may modify this risk.

A healthy lifestyle mitigates the risk of heart disease related to type 2 diabetes: a prospective nested case-control study in a nationwide Swedish twin cohort

AIMS/HYPOTHESIS

We aimed to examine the association between type 2 diabetes and major subtypes of heart disease, to assess the role of genetic and early-life familial environmental factors in this association and to explore whether and to what extent a healthy lifestyle mitigates the risk of heart disease related to type 2 diabetes.

METHODS

In this prospective nested case-control study based on the Swedish Twin Registry, 41,463 twin individuals who were aged ≥40 and heart disease-free were followed up for 16 years (from 1998 to 2014) to detect incident heart disease. Type 2 diabetes was ascertained from self-report, the National Patient Registry and glucose-lowering medication use. Heart disease diagnosis (including coronary heart disease, cardiac arrhythmias and heart failure) and onset age were identified from the National Patient Registry. Healthy lifestyle-related factors consisted of being a non-smoker, no/mild alcohol consumption, regular physical activity and being non-overweight. Participants were divided into three groups according to the number of lifestyle-related factors: (1) unfavourable (participants who had no or only one healthy lifestyle factor); (2) intermediate (any two or three); and (3) favourable (four). Generalised estimating equation models for unmatched case-control design and conditional logistic regression for co-twin control design were used in data analyses.

RESULTS

Of all participants, 2304 (5.5%) had type 2 diabetes at baseline. During the observation period, 9262 (22.3%) had any incident heart disease. In unmatched case-control analyses and co-twin control analyses, the multi-adjusted OR and 95% CI of heart disease related to type 2 diabetes was 4.36 (3.95, 4.81) and 4.89 (3.88, 6.16), respectively. The difference in ORs from unmatched case-control analyses vs co-twin control analyses was statistically significant (OR 1.57; 95% CI 1.42, 1.73; p < 0.001). In stratified analyses by type 2 diabetes, compared with an unfavourable lifestyle, an intermediate lifestyle or a favourable lifestyle was associated with a significant 32% (OR 0.68; 95% CI 0.49, 0.93) or 56% (OR 0.44; 95% CI 0.30, 0.63) decrease in heart disease risk among patients with type 2 diabetes, respectively. There were significant additive and multiplicative interactions between lifestyle and type 2 diabetes on heart disease.

CONCLUSIONS/INTERPRETATION

Type 2 diabetes is associated with more than fourfold increased risk of heart disease. The association still remains statistically significant, even after fully controlling for genetic and early-life familial environmental factors. However, greater adherence to a healthy lifestyle may significantly mitigate the risk of heart disease related to type 2 diabetes. Graphical abstract.

Evaluation of the body mass index in breast cancer prognosis in a cohort of small-stature overweight patients: multi-center study in China

Background

Overweight and obesity have become a major health issue in the past 30 years. Several studies have already shown that obesity is significantly associated with a higher risk of developing breast cancer. However, few studies have assessed the prognostic value of the body mass index (BMI) in Asian populations. The purpose of this study was to retrospectively analyze the impact of BMI on the prognosis of breast cancer in overweight, under 160 cm tall patients from southern China.

Methods

We retrospectively analyzed data from 525 breast cancer patients diagnosed between 2003 to 2010 in a multi-center of China. After applying the exclusion criteria, 315 patients with complete data were retained. Their clinical and pathological characteristics were compared using the chi-square test. Survival analysis was performed with the Kaplan-Meier method. Univariate and multivariate analyses were performed using Cox regression to calculate hormone receptor status, HER-2 status, lymph node status, age, BMI and tumor size hazard ratio (HR), and 95% confidence intervals (95% CI).

Results

There was a strong correlation between BMI and age in the baseline feature analysis (P=0.001). After grouping the patients according to the molecular type of cancer, we found that in Luminal A and B, the BMI was related to age (P=0.002, P=0.010). The disease-free survival (DFS) and overall survival (OS) of patients with different BMI were not significantly different. This conclusion was also reached by pairwise comparison of subgroups. There was no significant difference in recurrence in patients from different BMI groups. We did not find a critical weight threshold associated with higher risk of recurrence. There were no statistically significant differences in treatment among the three BMI groups of overweight patients.

Conclusions

We found that the BMI of Chinese breast cancer patients is related to age but not prognosis.

The Roles of Genetic and Early-Life Environmental Factors in the Association Between Overweight or Obesity and Hypertension: A Population-Based Twin Study

AIMS/HYPOTHESIS

We aimed to explore whether and to what extent overweight or obesity could increase the risk of hypertension, and further to estimate the roles of genetic and early-life familial environmental factors in their association.

METHODS

This prospective twin study was based on the Chinese National Twin Registry (CNTR), which collected information from self-report questionnaires. We conducted unmatched case-control analysis to examine the association between overweight or obesity and hypertension. And further to explore whether genetics and familiar environments shared within a twin pair, accounted for their association via co-twin matched case-control design. Generalized estimating equation (GEE) models and conditional logistic regressions were used in the unmatched and matched analyses, respectively. Then, we used logistic regressions to test the difference in odds ratios (ORs) between the unmatched and matched analyses. Finally, through bivariate twin model, the roles of genetic and environmental factors in the body mass index (BMI)- hypertension association were estimated.

RESULTS

Overall, we included a total of 30,617 twin individuals, of which 7533 (24.6%) twin participants were overweight or obesity and 757 (2.5%) developed hypertension during a median follow-up time of 4.4 years. In the GEE model, overweight or obesity was associated with a 94% increased risk of hypertension (OR=1.94, 95% confidence interval (CI): 1.64~2.30). In the conditional logistic regression, the multi-adjusted OR was 1.80 (95% CI: 1.18~2.74). The difference in OR between unmatched and matched analyses was significant (P=0.016). Specifically, overweight or obesity was not associated with hypertension risk in the co-twin design when we full controlled genetic and familiar environmental factors (OR=0.89, 95 CI: 0.46~1.72). After controlling for age and sex, we found the positive BMI-hypertension association was mainly explained by a genetic correlation between them (r_A= 0.59, 95% CI: 0.44~1.00).

CONCLUSIONS/INTERPRETATION

Genetics and early-life environments shared by participants within a twin pair appear to account for the association between overweight or obesity and hypertension risk.

Type 2 diabetes in midlife and risk of cerebrovascular disease in late life: a prospective nested case-control study in a nationwide Swedish twin cohort

AIMS/HYPOTHESIS

We aimed to examine the association between midlife type 2 diabetes mellitus and cerebrovascular disease (CBD) in late life, and further to explore whether genetic and early-life familial environmental factors (such as shared childhood socioeconomic status and adolescent environment) play a role in this association.

METHODS

In this prospective nested case-control study based on the Swedish Twin Registry, 33,086 twin individuals who were born in 1958 or earlier and were CBD-free before the age of 60 were included. Midlife (40-59 years) type 2 diabetes was ascertained from self-report, the National Patient Registry (NPR) and glucose-lowering medication use. CBD diagnosis (cerebral infarction, occlusion of cerebral arteries, subarachnoid haemorrhage, intracerebral haemorrhage and unspecified CBD) and onset age were identified from the NPR. Late-life CBD was defined as CBD onset age ≥60 years. Generalised estimating equation (GEE) models were used to analyse unmatched case-control data (adjusted for the clustering of twins within a pair). Conditional logistic regression was used in co-twin matched case-control analyses in CBD-discordant twin pairs.

RESULTS

Of all the participants, 1248 (3.8%) had midlife type 2 diabetes and 3121 (9.4%) had CBD in late life. In GEE models adjusted for age, sex, education, BMI, smoking, alcohol consumption, marital status, hypertension and heart disease, the ORs (95% CIs) of type 2 diabetes were 1.29 (1.03, 1.61) for cerebral infarction, 2.03 (1.20, 3.44) for occlusion of cerebral arteries, 0.52 (0.12, 2.21) for subarachnoid haemorrhage and 0.78 (0.45, 1.36) for intracerebral haemorrhage. In multi-adjusted conditional logistic regression, the OR of the type 2 diabetes-cerebral infarction association was 0.96 (0.51, 1.80). The differences in ORs from the GEE and co-twin control analyses were not statistically significant (p = 0.780).

CONCLUSIONS/INTERPRETATION

Midlife type 2 diabetes is significantly associated with increased risk of cerebral infarction and occlusion of cerebral arteries, but not intracerebral haemorrhage or subarachnoid haemorrhage in late life. Genetic and early-life familial environmental factors do not appear to account for the type 2 diabetes-cerebral infarction association, but further clarification is needed.

Co-Twin Control Studies: Natural Events, Experimental Interventions and Rare Happenings/Twin Research: Cancer Risk in Overweight Twins; Prognosis After Fetal Loss of One Twin; Twin Concordance for Parkinson's Disease; Neuroanatomy of Musically Discordant MZ Twins/News Articles: Twin Birth with Two Wombs; Twins' Prenatal Interactions; Switched-at-Birth Twins; Fetus-in-Fetu; Unsolved Paternity

Co-twin control is a well-known methodological twin research design, but its variations and complexities are less well known. Various issues and illustrations are presented with reference to studies involving natural events, experimental interventions and rare happenings that underlie monozygotic (MZ) twins' environmental differences. This discussion is followed by summaries of recent twin research pertaining to cancer risk in overweight twins, the physical risk to surviving twins after fetal loss of a co-twin, a 20-year update of twin concordance for Parkinson's disease, and neuroanatomical differences in musically discordant MZ twin pairs. Several twin-related items that have attracted attention in the news are also summarized.