Physical activity trajectories and mortality: population based cohort study
BMJ 2019; 365 doi: https://doi.org/10.1136/bmj.l2323 (Published 26 June 2019) Cite this as: BMJ 2019;365:l2323All rapid responses
Rapid responses are electronic comments to the editor. They enable our users to debate issues raised in articles published on bmj.com. A rapid response is first posted online. If you need the URL (web address) of an individual response, simply click on the response headline and copy the URL from the browser window. A proportion of responses will, after editing, be published online and in the print journal as letters, which are indexed in PubMed. Rapid responses are not indexed in PubMed and they are not journal articles. The BMJ reserves the right to remove responses which are being wilfully misrepresented as published articles or when it is brought to our attention that a response spreads misinformation.
From March 2022, the word limit for rapid responses will be 600 words not including references and author details. We will no longer post responses that exceed this limit.
The word limit for letters selected from posted responses remains 300 words.
Since the beginning of this millennium, governments around the World, year after year, have expressed their dissatisfaction with the direct relationship between the annual progressive increase in the budget for the health sector and the corresponding significant increase in morbidity and mortality rates for diseases such as diabetes, hypertension, heart failure, cancer, arthritis, neurodegenerative diseases, and respiratory disorders among people. Many of them have sent deep messages to the Four Winds questioning the traditional dynamics of the health sector, with a fixed idea, often expressed by those who wish to tear up the traditional concept of health care, which, it seems, always seeks to favor unscrupulous groups of people who only seek to enrich themselves around the suffering of patients by promoting only a medical culture directed towards the establishment of surgical treatment or palliative one. It is an anti-health system, whose main protagonists will hardly be able to change their attitude, their style of work and procedures. It’s urgent and indispensable to promote radical cultural changes in people daily’s life, to improve methods for early chronic disease diagnosis, and to increase the standards of physical activity, sanitation, nutrition and housing.
The health system that currently prevails in Colombia has never had strong public support and, like what happens in other countries, we must begin to put its dynamics in order. It's time to start changing.
In all countries the most expensive health care costs are in emergency rooms and treatment of patients with chronic preventive illnesses. Possibly for this reason all candidates, as a meaningful part of their presidential campaigns announce plans to make reforms in health care around primary prevention of non-communicable diseases. They focus on low cost, easy to implement and community wide strategies.
While the exact cause of chronic disease is not known, some light has been shade on bad mitochondrial activity in the development of at least cardiovascular and neurodegenerative diseases.
Mitochondrion is the energetic power plant of the cell. In its inside only the amount of ATP that the cell needs at a given time is produced. If to the cell enters more glucose than it normally needs, the remainder chemical energy goes on cytoplasm by metabolic pathways that lead to the formation of lipids and other compounds associated with the etiology and pathogenesis of several chronic diseases. It seems that chemical energy that enters to the organism must be burned; excessive intake of fuel molecules may be the problem. Excessive carbohydrate consumption accompanied by sedentary lifestyle can be an important factor in the emergence of chronic disease. So the key is, every day to consume foods of high biological value in normal quantities and move for burning the entering excess fuel.
Promoting exercise from early age provides a real opportunity to reduce the high indexes of morbidity and mortality by chronic disease as we can deduce from systematic review, done with a population of almost 15000 people, in England by Dr. Alexander Mok and cols. and published in BMJ 2019;365:l2323 electronic issue.
The name of our research group is PACA. This word is a four letters acronym. Its original meaning is Action Program to an Alternative Curriculum. The group's strategy is to promote significant changes in people's behavior through significant learning from experience and health metrics. In English we can translate the PACA dynamics as something like Preparing people for doing physical Activity, being wonderful Citizens, with good Attitudes toward their life. In our group we want to increase the effectiveness of using the great possibilities of physical activity to strengthen the people’s health from very early age as a preventive strategy, which will allow a harmonious development of all body functions, mainly those related to the individual and collective personality, which will result in a significant increase in the people’s quality of life, and a significant decrease in the rates of morbidity and mortality due to chronic diseases. It is very important to carry out longitudinal studies that allow regular and permanent assessment of the physical fitness of people, their physical functioning, from the age of six to the rest of their lives.
Competing interests: We are an active part of the daily dynamics of the PACA research group, classified in category 1A, by COLCIENCIAS, the official entity that regulates scientific research in Colombia.
Additional data requested, confounding is likely
The authors report data of a highly selected subgroup (57% subjects with repeated measurements available approximately a decade after recruitment) of a cohort already consisting of selected patients recruited from general practices.
The authors claim that “At the population level, meeting and maintaining at least the minimum physical activity recommendations would potentially prevent 46% of deaths associated with physical inactivity.”
The study presents lower risks for all-cause mortality (HR 0.76, 95%CI 0.71 to 0.82) and cardiovascular disease mortality (0.71, 0.62 to 0.82), whereas HR were only marginally significant for cancer mortality (0.89, 95% CI 0.79 to 1.00). [There is a discrepancy to the upper 95%CI limit of 0.99 reported in the abstract.]
Unexpectedly, hazard ratios were strengthened rather than attenuated after adjusting for established cardiometabolic risk factors indicating potential unmeasured confounding.
Most importantly, a third of deaths was unrelated to cardiovascular disease (a third of deaths) or cancer (also a third of deaths). Nonetheless, overall hazard ratios for all-cause mortality were comparably low as for cardiovascular mortality. This is surprising as one would assume that physical activity scores are not related to deaths that are not attributed to physical inactivity. In fact, due to competing causes of death hazard ratios might even be expected to increase.
Therefore, could the authors provide additional analyses on the association between the remaining group of deaths (originally categorized as unrelated to physical activity) and physical activity scores? Lower mortality risks would support bias and confounding rather than a causal relationship between physical activity and mortality as suggested by the authors.
Competing interests: No competing interests