Life expectancy associated with different ages at diagnosis of type 2 diabetes in high-income countries: 23 million person-years of observation

BACKGROUND

The prevalence of type 2 diabetes is increasing rapidly, particularly among younger age groups. Estimates suggest that people with diabetes die, on average, 6 years earlier than people without diabetes. We aimed to provide reliable estimates of the associations between age at diagnosis of diabetes and all-cause mortality, cause-specific mortality, and reductions in life expectancy.

METHODS

For this observational study, we conducted a combined analysis of individual-participant data from 19 high-income countries using two large-scale data sources: the Emerging Risk Factors Collaboration (96 cohorts, median baseline years 1961-2007, median latest follow-up years 1980-2013) and the UK Biobank (median baseline year 2006, median latest follow-up year 2020). We calculated age-adjusted and sex-adjusted hazard ratios (HRs) for all-cause mortality according to age at diagnosis of diabetes using data from 1 515 718 participants, in whom deaths were recorded during 23·1 million person-years of follow-up. We estimated cumulative survival by applying age-specific HRs to age-specific death rates from 2015 for the USA and the EU.

FINDINGS

For participants with diabetes, we observed a linear dose-response association between earlier age at diagnosis and higher risk of all-cause mortality compared with participants without diabetes. HRs were 2·69 (95% CI 2·43-2·97) when diagnosed at 30-39 years, 2·26 (2·08-2·45) at 40-49 years, 1·84 (1·72-1·97) at 50-59 years, 1·57 (1·47-1·67) at 60-69 years, and 1·39 (1·29-1·51) at 70 years and older. HRs per decade of earlier diagnosis were similar for men and women. Using death rates from the USA, a 50-year-old individual with diabetes died on average 14 years earlier when diagnosed aged 30 years, 10 years earlier when diagnosed aged 40 years, or 6 years earlier when diagnosed aged 50 years than an individual without diabetes. Using EU death rates, the corresponding estimates were 13, 9, or 5 years earlier.

INTERPRETATION

Every decade of earlier diagnosis of diabetes was associated with about 3-4 years of lower life expectancy, highlighting the need to develop and implement interventions that prevent or delay the onset of diabetes and to intensify the treatment of risk factors among young adults diagnosed with diabetes.

FUNDING

British Heart Foundation, Medical Research Council, National Institute for Health and Care Research, and Health Data Research UK.

P6222Changes in main CVD risk factors in Finland 1992–2017

Background

Systematic monitoring of cardiovascular disease (CVD) risk factors started in eastern Finland already in the 1970s as part of the North Karelia Project. Later on risk factor monitoring was extended to other parts of the country.

Purpose

In this study we report the trends of main CVD risk factors in Finland from 1992 to 2017.

Methods

Study population consists of a population-based random sample of 31 402 men and women aged 25–64 years who participated in the FINRISK Studies from 1992 to 2012, and in the FinHealth Study in 2017. Data collection was done every five years. Participation rate decreased from 76% in 1992 to 56% in 2017. Study protocol included self-reported questionnaire data on smoking and other health behavior, measurements of height, weight and blood pressure, and venous blood sample for laboratory analysis. Blood pressure was measured two times, and the average of the measurements was calculated, total serum cholesterol was analyzed using enzymatic method, and LDL cholesterol was calculated using Friedewald formula.

Results

Smoking prevalence, mean blood pressure and total and LDL cholesterol levels declined markedly during the 25 year follow up but BMI, waist circumference and prevalence of obesity increased (table).

CVD risk factor change from 1992 to 2017 Risk factor Men 1992 Men 2017 p value Women 1992 Women 2017 p value Smoking (%) 36.7 20.6 <0.001 25.9 16.5 <0.001 SBP (mmHg) 136.6 131.2 <0.001 130.3 124.5 <0.001 DBP (mmHg) 82.7 81.6 <0.001 78.6 77.8 <0.001 Chol (mmol/L) 5.66 5.17 <0.001 5.42 5.18 <0.001 LDL chol (mmol/L) 3.54 3.16 <0.001 3.26 3.03 <0.001 BMI (kg/m2) 26.2 27.2 <0.001 25.1 26.4 <0.001 WC (cm) 92.8 96.1 <0.001 79.2 86.2 <0.001 Obesity (%) 15.7 23.2 <0.001 14.8 22.7 <0.001

Conclusions

The levels of main traditional CVD risk factors have markedly decreased among the Finnish population during the last 25 years but in the same time, obesity has become a major public health challenge.

Changes in body mass index and measures of abdominal obesity in Finnish adults between 1992 and 2007, the National FINRISK Study

What is already known about this subject •  Recent obesity trends across the world in adults are mixed, varying from showing signs of levelling off to a continuously increasing prevalence. •  Secular trends in body mass index (BMI) and waist circumference may vary by sex and age. •  Relying exclusively on BMI data may lead to underestimate the obesity epidemic. What this study adds •  Adverse trends in obesity indicators have continued in Finland in the 2000s. •  In older men, BMI remained quite stable and in older women BMI has decreased since 1997. •  Steep upward trends in abdominal obesity (waist circumference and waist-to-height ratio, WHtR) have taken place in both men and women and in all age groups, especially during the past 10 years. •  The impact of BMI adjustment on trends in abdominal obesity varied by age such that increases in BMI-adjusted waist circumference and WHtR were more prominent in older age groups.

SUMMARY

Signs that obesity trends will level off at the turn of the 21st century have been reported. In these studies, however, the definition of obesity has been based only on body mass index (BMI). We investigated obesity trends among Finnish adults over recent years by using BMI, waist circumference and waist-to-height ratio as indicators for obesity. Data were derived from the national FINRISK surveys, which are cross-sectional population surveys conducted at 5-year intervals between 1992 and 2007. Altogether, 20 551 randomly selected men and women aged 25-64 years participated in health examinations, where weight, height, and waist and hip circumferences were measured by trained nurses. Mean BMI increased in younger men and women (aged 25-44 years) between 1992 and 2007, whereas in older men, BMI remained quite stable and in older women BMI has decreased since 1997. Nevertheless, mean waist circumference and waist-to-height ratio increased in both men and women over the 15-year period. The upward trends took place in all age groups, especially during the past 10 years. Adverse trends in obesity indicators have continued in Finland in the 2000s. In particular, concerns are related to steep upward trends in abdominal obesity.

Systematically missing confounders in individual participant data meta-analysis of observational cohort studies

One difficulty in performing meta-analyses of observational cohort studies is that the availability of confounders may vary between cohorts, so that some cohorts provide fully adjusted analyses while others only provide partially adjusted analyses. Commonly, analyses of the association between an exposure and disease either are restricted to cohorts with full confounder information, or use all cohorts but do not fully adjust for confounding. We propose using a bivariate random-effects meta-analysis model to use information from all available cohorts while still adjusting for all the potential confounders. Our method uses both the fully adjusted and the partially adjusted estimated effects in the cohorts with full confounder information, together with an estimate of their within-cohort correlation. The method is applied to estimate the association between fibrinogen level and coronary heart disease incidence using data from 154 012 participants in 31 cohorts.† Copyright © 2009 John Wiley & Sons, Ltd.

Changes in traditional risk factors no longer explain time trends in cardiovascular mortality and its socioeconomic differences

AIM

To investigate to what extent the changes in traditional risk factors (total cholesterol, smoking, hypertension) explain the changes in socioeconomic (defined by occupational class and household income) differences in cardiovascular mortality in Finland during the past 20 years.

DESIGN

Study population comprised 14,642 men and women aged 35-64 years who were selected from population-based FINRISK surveys in 1987, 1992, 1997 or 2002 in three areas of Finland. The 1982 and 1987 FINRISK cohorts were used to determine a model for the probability of cardiovascular death based on risk factor values at the baseline for each socioeconomic group. These predicted changes in cardiovascular mortality were then contrasted with observed mortality rates in different socioeconomic groups to determine the contribution of the changes in risk factors to changes in actual mortality.

RESULTS

We found that among men during 1987-97, when risk factor levels were improving in all socioeconomic groups, the model explained 29-44% of the observed mortality decline. The risk factors explained a larger part of the decline among lower socioeconomic groups. During the period 1997-2002 the risk factor levels stopped improving in all socioeconomic groups but observed mortality rates kept declining. The predicted mortality rates were 16-34% of the observed rates during the period 1987-2002.

CONCLUSIONS

Changes in traditional risk factors no longer provide a good explanation of the changes in cardiovascular mortality and its socioeconomic differences. However, risk factors did explain the cardiovascular mortality decline among lower socioeconomic groups.

The Emerging Risk Factors Collaboration: analysis of individual data on lipid, inflammatory and other markers in over 1.1 million participants in 104 prospective studies of cardiovascular diseases

Many long-term prospective studies have reported on associations of cardiovascular diseases with circulating lipid markers and/or inflammatory markers. Studies have not, however, generally been designed to provide reliable estimates under different circumstances and to correct for within-person variability. The Emerging Risk Factors Collaboration has established a central database on over 1.1 million participants from 104 prospective population-based studies, in which subsets have information on lipid and inflammatory markers, other characteristics, as well as major cardiovascular morbidity and cause-specific mortality. Information on repeat measurements on relevant characteristics has been collected in approximately 340,000 participants to enable estimation of and correction for within-person variability. Re-analysis of individual data will yield up to approximately 69,000 incident fatal or nonfatal first ever major cardiovascular outcomes recorded during about 11.7 million person years at risk. The primary analyses will involve age-specific regression models in people without known baseline cardiovascular disease in relation to fatal or nonfatal first ever coronary heart disease outcomes. This initiative will characterize more precisely and in greater detail than has previously been possible the shape and strength of the age- and sex-specific associations of several lipid and inflammatory markers with incident coronary heart disease outcomes (and, secondarily, with other incident cardiovascular outcomes) under a wide range of circumstances. It will, therefore, help to determine to what extent such associations are independent from possible confounding factors and to what extent such markers (separately and in combination) provide incremental predictive value.

Plasma fibrinogen level and the risk of major cardiovascular diseases and nonvascular mortality: an individual participant meta-analysis

CONTEXT

Plasma fibrinogen levels may be associated with the risk of coronary heart disease (CHD) and stroke.

OBJECTIVE

To assess the relationships of fibrinogen levels with risk of major vascular and with risk of nonvascular outcomes based on individual participant data.

DATA SOURCES

Relevant studies were identified by computer-assisted searches, hand searches of reference lists, and personal communication with relevant investigators.

STUDY SELECTION

All identified prospective studies were included with information available on baseline fibrinogen levels and details of subsequent major vascular morbidity and/or cause-specific mortality during at least 1 year of follow-up. Studies were excluded if they recruited participants on the basis of having had a previous history of cardiovascular disease; participants with known preexisting CHD or stroke were excluded.

DATA EXTRACTION

Individual records were provided on each of 154,211 participants in 31 prospective studies. During 1.38 million person-years of follow-up, there were 6944 first nonfatal myocardial infarctions or stroke events and 13,210 deaths. Cause-specific mortality was generally available. Analyses involved proportional hazards modeling with adjustment for confounding by known cardiovascular risk factors and for regression dilution bias.

DATA SYNTHESIS

Within each age group considered (40-59, 60-69, and > or =70 years), there was an approximately log-linear association with usual fibrinogen level for the risk of any CHD, any stroke, other vascular (eg, non-CHD, nonstroke) mortality, and nonvascular mortality. There was no evidence of a threshold within the range of usual fibrinogen level studied at any age. The age- and sex- adjusted hazard ratio per 1-g/L increase in usual fibrinogen level for CHD was 2.42 (95% confidence interval [CI], 2.24-2.60); stroke, 2.06 (95% CI, 1.83-2.33); other vascular mortality, 2.76 (95% CI, 2.28-3.35); and nonvascular mortality, 2.03 (95% CI, 1.90-2.18). The hazard ratios for CHD and stroke were reduced to about 1.8 after further adjustment for measured values of several established vascular risk factors. In a subset of 7011 participants with available C-reactive protein values, the findings for CHD were essentially unchanged following additional adjustment for C-reactive protein. The associations of fibrinogen level with CHD or stroke did not differ substantially according to sex, smoking, blood pressure, blood lipid levels, or several features of study design.

CONCLUSIONS

In this large individual participant meta-analysis, moderately strong associations were found between usual plasma fibrinogen level and the risks of CHD, stroke, other vascular mortality, and nonvascular mortality in a wide range of circumstances in healthy middle-aged adults. Assessment of any causal relevance of elevated fibrinogen levels to disease requires additional research.