Researchers at Lund University in Sweden announced on Apr. 11 that gaining weight earlier in adulthood is linked to a greater risk of dying from various diseases later in life. The findings come from a study involving over 600,000 people, which examined how changes in weight between the ages of 17 and 60 relate to long-term health outcomes.
The timing of weight gain appears to play an important role in future health risks. According to the researchers, individuals who developed obesity between ages 17 and 29 faced about a 70 percent higher risk of premature death compared with those who did not become obese before age 60. Obesity onset was defined as reaching a body mass index (BMI) of 30 or higher for the first time.
"One possible explanation for why people with early obesity onset are at greater risk is their longer period exposed to the biological effects of excess weight," said Huyen Le, doctoral student at Lund University and first author of the study.
However, when looking specifically at cancer in women, researchers found that "the risk was roughly the same regardless of when the weight gain occurred," Le said. This suggests that other biological mechanisms may influence cancer risk and survival among women beyond just long-term exposure to obesity. Hormonal changes associated with menopause could be one such factor: "If our findings among women reflect what happens during menopause, the question is which came first: the chicken or the egg? It may be that hormonal changes affect weight and the age and duration over which these changes occur – and that weight simply reflects what's happening in the body," Le added.
The study's strength lies in its use of multiple objective measurements per individual taken by staff—such as during healthcare visits—rather than relying on self-reported data. "The predominance of objectively measured weights in our study contributes to more reliable and robust results," said Tanja Stocks, another researcher involved.
Stocks also noted that while exact figures can be influenced by various factors, recognizing patterns remains crucial: "But we shouldn't get too hung up on exact risk figures... it's important to recognise the patterns, and this study sends an important message to decision-makers and politicians regarding the importance of preventing obesity." She emphasized that societal factors contribute significantly: "It's up to policymakers to implement measures that we know are effective in combating obesity. This study provides further evidence that such measures are likely to have a positive impact on people's health."
