Impact of a type 2 diabetes diagnosis on mental health, quality of life, and social contacts: a longitudinal study

Introduction

Type 2 Diabetes Mellitus (T2DM) is a preventable non-communicable disease requiring a multifactorial approach to management that incorporates lifestyle change and pharmacotherapy.1 Less than ideal management increases the risk of developing complications and comorbidities such as cardiovascular disease (CVD)2 and various unfavorable social and economic penalties.3 Unfortunately, many hurdles remain for the effective management of T2DM.4 The potential toll that a T2DM diagnosis has on mental health is a major concern.5 Depression is more prevalent among people living with T2DM compared with those who are not6 and increases the risk of premature death.7 Studies suggest that the presence of minor psychological morbidity increases non-adherence to T2DM treatment.8 ,9 Elevated stress levels as a result of becoming aware of a T2DM diagnosis may be an underlying cause of worsening mental health, which could also have negative impacts on overall quality of life such as the levels of contact a person may have with friends and family. With rising awareness of T2DM-related stigma,10–12 it may be that many people receiving a diagnosis avoid contact with (or are shunned by) others due to a fear that they may be blamed for their T2DM status, as has been observed among people with liver and lung-related health problems.13–16

The impact of a T2DM diagnosis on mental health and quality of life has been previously investigated but the vast majority of studies employed cross-sectional designs make it very challenging to infer a causal relationship. This is likely to be a major factor behind the mixture of findings reported, with some meta-analyses indicating a low to modest increase in risk of experiencing depression among people living with T2DM,17 ,18 whereas other studies suggest no change in mental health as a result of T2DM diagnosis19 or instead report depression as a risk factor for T2DM.18 ,20 Longitudinal data affords the opportunity to surmount this challenge, but since diabetes status cannot be randomly assigned, this still leaves the door open for confounding. Personality traits that may be consistent over time, for example, like negative affect, may influence mental health, quality of life, and the levels of social contact a person has with others as well as T2DM risk more generally.21 Resolving these issues is crucial to bolster adherence to pharmacotherapy regimens and participation in lifestyle modification programs, and to underline the need for investments in initiatives seeking to support mental health and to ameliorate the risk of social isolation among people with T2DM.22

The purpose of this study was to use a longitudinal study design to examine for potential impacts of a T2DM diagnosis on mental health, quality of life, and a range of types of social contact.

Results

From a sample of 26 344 participants, there were 586 new diagnoses of T2DM by the follow-up survey (table 1). The prevalence of psychological distress and poor quality of life increased between baseline and follow-up, while the mean count of social contacts decreased across all four indicators. Annual household income shifted upwards for much of the sample over time. Retirement became more common in general, whereas economic inactivity reduced notably.

In fixed effects models adjusted for age (table 2), a modest increase in the odds of experiencing psychological distress was associated with T2DM diagnosis (OR=1.31), but the 95% CIs spanned unity (0.76 to 2.25). In contrast, a T2DM diagnosis was associated with a fivefold increase in the odds of a participant reporting that their quality of life had become significantly poorer (OR 5.54, 95% CI 1.28 to 24.10). T2DM diagnosis was also associated with a reduction in social contacts across all four types. Further adjustment for time-varying confounders had a negligible impact on the results.

Discussion

The key findings from this study contribute to understandings of T2DM in the following ways: first, the longitudinal fixed effects design afforded insights in to the extent that a recent T2DM diagnosis is implicated in worsening mental health, poorer quality of life, and reduced social contacts while eliminating sources of confounding that typically manifest in prior (mostly cross-sectional) research; second, the evidence for a T2DM diagnosis leading to an experience of psychological distress was found to be not particularly strong; however, third, the decline in quality of life and across all four social contact outcomes as a consequence of T2DM diagnosis was compelling. Taken collectively, this suggests that a T2DM diagnosis does have significant impacts across a range of circumstances that a person may hold important to themselves that are not typically captured by well-known and validated measures of mental health such as the K10. Circumstances such as whether a person feels they can draw on the support of a social network, which prior research has already shown, do play an important role in mental health trajectories as well as all other aspects of life.31 These are circumstances that also likely play a role in shaping whether people are able to adhere to lifestyle modification programs, pharmacotherapy regimens, and the regular visits to general practitioners that are staple of T2DM management. Therefore, declining quality of life and increasing social isolation among people who are recently diagnosed with T2DM are scenarios that ought to be monitored closely by general practitioners and the local health sector if devastating and hugely expensive, but preventable comorbidities and complications are to be successfully avoided.

Aside from the study design, the range of outcome variables is a clear strength of the study. The separate indicator of quality of life afforded an insight that would not have been made had the K10 been relied on solely. However, it is important to recognize that there are a range of ways to measure mental health and while the K10 is a validated and widely used tool, others such as the Warwick-Edinburgh Mental Well-being Scale32 and the WHO's 5-Item Well-Being Index,33 which focus more on positive circumstances could also have provided different insights, were those included in the surveys. Likewise, the four indicators of social contacts provided inroads into understanding the degree to which a T2DM diagnosis may increase a person's risk of becoming socially isolated. However, other indicators such as those relating to trust in other people, feelings of exclusion related to T2DM stigma, and new contacts resulting from participation in networks specifically related to T2DM (eg, a support program coordinated by a general practitioner) would also have been of interest to examine had data been available. Furthermore, it would be important (if sample sizes and relevant data allow) for future research to consider how impacts of a T2DM diagnosis on mental health, quality of life, and social contacts may vary between different ethnic and racial groups. It is known that there are important variations in each of these factors, as well as access to health-related information and healthcare between ethnic and racial groups in many countries around the world.34–37 Those analyses would provide data that could be used to help devise culturally sensitive strategies that aim to eliminate inequity in the impacts of T2DM within society.

This study is limited by the length of follow-up and that there were only two data points available for each participant. An enhanced analytical strategy in future, pending data availability, would be to examine the impact of a T2DM diagnosis on each outcome in the short-term, as was the case in this study, and in the long-term over many successive waves of data collection. This is important as there are contrasting theories on the long-term consequences that a life changing event like a T2DM diagnosis could set in motion. In the best case scenario, it may be that after the initial shock that many people will experience on being diagnosed with T2DM and subsequent life changes and management strategies that they often must (or ought to) implement, these changes may become less burdensome over time as people gradually adapt to new routines.38 ,39 This is described as a best case scenario since for this to occur it is likely that people will need support structures around them—socially and financially—but as this study has reported, social contacts tended to reduce across the board following a T2DM diagnosis. Evidence already shows that T2DM is a disease over-represented among the socioeconomically disadvantaged,40 which puts the adaptation hypothesis into some doubt. Drawing on the theory of accumulation within lifecourse epidemiology,41 in contrast, it is possible that if the reduced social contacts and quality of life observed in this study are sustained, then that may lead to an increased odds of experiencing psychological distress (as well as other unfavorable outcomes) further down the line.42 Long-term follow-up is henceforth desirable for informing decision-makers on what initiatives can help support people to manage their T2DM effectively without negative impacts on their quality of life.