In a recent study published in Lancet Public HealthResearchers examined the associations between body mass index (BMI) in early maturity and heart problems in a Chinese population, in addition to the influence of lifestyle aspects in midlife on these outcomes.

The outcomes indicate that a better BMI in early maturity is related to a better risk of heart problems, suggesting that early maturity is a key period for obesity prevention and weight management to keep up cardiovascular health in later life.

Test: Early maturity BMI and heart problems: a prospective cohort study from China Kadoorie Biobank. Image Source: ProfDesigner / Shutterstock

Background

Obesity amongst middle-aged adults is a recognized risk factor for heart problems resulting in early mortality, but less is thought concerning the impact of weight in early maturity. Early maturity, often a critical period for weight gain, has seen a worldwide increase in obesity and obese rates.

For instance, in China, the common BMI of individuals aged 18 to 39 years increased from lower than 22 kg/m² in 1993 to greater than 23 kg/m² in 2015. Previous research in Western countries suggests that obesity and obese in early maturity can lead to varied health problems, including heart problems, but there is restricted evidence from Asian populations.

Asians often have greater abdominal obesity and body fat than whites of comparable BMI, which increases the chance of developing cardiometabolic disease at lower BMI levels. The association between being underweight and cardiovascular risk is unclear, and studies have shown mixed results. As well as, more data are needed on hemorrhagic stroke, particularly in China, where it’s more common.

In regards to the study

The researchers tracked participants aged 30–79 years from five urban and five rural areas. Between 2004 and 2008, participants were surveyed and provided information via interviews, physical measurements, and written consent.

We excluded individuals with a history of heart disease, stroke, cancer, or diabetes at baseline, in addition to individuals outside the age range of 35–70 years or with missing BMI data at age 25 years. Body weight in early maturity was self-reported, and BMI was calculated from this weight and height at baseline. Lifestyle aspects similar to smoking, drinking, physical activity, and food plan were assessed using questionnaires.

The first outcomes of the study were the incidence of heart problems, including coronary heart disease, hemorrhagic stroke, and ischemic stroke, tracked through disease and death registries and medical insurance claims.

The researchers used a Cox proportional hazards regression model to find out the association between a variable (similar to BMI) and the time it takes for an event to occur (similar to developing heart disease), while adjusting for other aspects.

The model allowed them to regulate for differences in gender, education, marital status, hypertension, and family history to make their findings more accurate. Additionally they checked out specific groups and conducted additional tests to see how changes in weight, age, and lifestyle habits in midlife might affect cardiovascular risk.

Results

After excluding individuals with heart disease, stroke, transient ischemic attack, cancer, or diabetes, the ultimate sample included 360,855 participants. The mean age of participants was 50 years, 42% were men and 58% were women. Participants had a mean BMI of just below 22 kg/m² in early maturity and almost 24 kg/m² in middle maturity.

Nearly half maintained a BMI below 24 kg/m² at each time points, while 26% who were initially classified as normal or underweight became obese and 6% became obese. Higher BMI in early maturity was related to lower educational attainment, higher prevalence of hypertension, and increased BMI in middle maturity.

Throughout the 12-year median follow-up period, 7% of participants died from any cause, and almost 2% died from heart problems. Overall, the researchers recorded 57,203 cases of heart problems, including 29,718 ischemic heart disease, 30,192 ischemic stroke, and 5,978 hemorrhagic stroke.

The danger of heart problems was positively related to BMI in early maturity, with participants with a BMI above 30 kg/m² experiencing a 58% higher risk than those with a lower BMI. Obesity, defined as a BMI above 28 kg/m² in early maturity, was related to a 39% higher likelihood of developing heart problems.

Higher BMI in early maturity was related to increased risk of coronary heart disease, ischemic stroke, and hemorrhagic stroke. As well as, being underweight was related to a rather lower risk of ischemic stroke and coronary heart disease.

Conclusions

The study found a positive association between higher BMI in early maturity and increased risk of developing heart problems within the Chinese population, which is consistent with findings from studies in america and Europe. Strengths of the study include the big sample size and prolonged follow-up period, although limitations include reliance on self-reported weight and lack of dynamic weight data.

The outcomes underscore the importance of formative years weight management in stopping CVD, emphasizing the necessity for initiatives targeted at young adults. Future studies should address lifestyle aspects in early maturity and dynamic weight changes to achieve a more comprehensive understanding.