# Exercise as it relates to Disease/Does incorporating more physical activity into everyday lifestyle improve body composition, thyroid function, and structure in obese children?
## What is the background to this research?

The Thyroid is a gland that sits in the front of the throat and is responsible for the secretion of several hormones responsible for influencing metabolism, growth and development and body temperature which is important in early life for normal growth and development in children. Weight excess correlates with several obesity-related conditions and thyroid structure and function is now considered among them. A study conducted on obese children between 2004 and 2008 displayed alterations in thyroid structure and function were present in obese individuals particularly in children. Function reverses to normal after weight loss, but not a lot is known about alterations to the thyroid structure. the study aimed to assess any improvements to thyroid structure as well as function following weight loss due to implementation of physical activity and structured diet into everyday lifestyle .

## Where is the research from?

The study was conducted over the course of 4 years from 2004 to 2008 by G. Radetti, S. Longhi, M. Baiocchi, W. Cassar, and F. Buzi, who are all affiliated with pediatrics studies. Giorgio Radetti, the main author of this work has done previous studies on the structure and function of the thyroid and how it is affected by obesity and weight loss. The Study was conducted at two Pediatric Endocrinology Centers, the Department of Pediatrics, Regional Hospital of Bolzano and the Department of Pediatrics, University of Brescia, Italy. This research was first published online on the 27th of May 2011 as part of the Journal of Endocrinological Investigation Issue 3, pp 281–285 .

## What kind of research was this?

This study is classified as a longitudinal follow-up study. Subjects are followed over time with continuous or repeated monitoring of risk factors or health outcomes, or both. The study is designed to verify the effectiveness of a dieting program together with participation in regular physical activity on reverting changes observed in thyroid structure of obese children. This study design is appropriate for desired research conclusions, and other studies done by Giorgio Radetti and others support the findings of the study with little differentiation in results of similar studies conducted. hormones before and after weight loss in obesity ,Function and Structure Are Affected in Childhood Obesity, Influences of obesity and weight loss on thyroid hormones

## What did the research involve?

Between March 2004 and September 2008, 72 overweight and obese children [body mass index (BMI) >85 percentile) (41 males, 31 females) were evaluated. Measurement of free T3 (fT3), free T4 (fT4), TSH, anti-thyroid-antibodies and a thyroid ultrasound was performed at the beginning (phase 1) and after a period of 1.8±1.0 years of lifestyle intervention (phase 2). Clinical characteristics assessed include, chronological age, bone age, height (SDS), BMI (SDS), fitness (hr/week), Fat mass(kg), fat mass percentage and fat free mass(kg).
The children assessed were part of a cohort of 186 obese children evaluated in a previous study Function and Structure Are Affected in Childhood Obesity, who agreed to follow a weight-management program at two Pediatric Endocrinology Centers.
The methodology was sound, as it accurately collected the clinical data showing a correlation between weight loss and thyroid structure over time with no major errors in data collection. The design of the study could improve as there is no detail about a set exercise or dietary plan, making it completely reliant on individual participation at a given exercise intensity and healthy diet choices. There are few ways to ensure participants follow the program strictly, short of constant monitoring of all 72 patients .
Limitations of this study:
* The children were all diagnosed with simple obesity, other syndrome, organic, and hormonal causes have been excluded from the study. None of the children showed signs of thyroid autoimmunity, nor were any of the subjects affected by diabetes. This means this study intervention cannot be applied to any chronic disease condition outside of simple obesity as a valid intervention.
* Studies are all done on children, so its unknown if this outcome of revered thyroid structure would occur in other population groups.
* the studies success is heavily reliant on the compliance of the children to the program and the results may be altered by how strictly the plan was followed over the 4 years the study was conducted for.
* The study does not mention a set diet and exercise plan and appears to be dependent on the individual patients motivation and lifestyles choices.

## What were the basic results?

The aim of this study was to verify whether changes in lifestyle might improve the alterations in thyroid function and structure that we previously showed in a group of obese children, without signs of thyroid autoimmunity. The weight-management program offered to the children was based mainly on modifications of their eating habits together with increased physical activity, with tests done at two stages. The children were examined for the first time at a mean age of 10.4±2.9 yr (phase 1) and subsequently at a mean age of 12.2±3.4 (phase 2)
| Clinical characteristics | Phase 1 | Phase 2 |
| Height | 0.7±0.9 | 0.6±0.9 |
| Chronological age | 10.4±2.9 | 12.2±3.4 |
| Bone age | 10.7±3.1 | 13.1±3.3 |
| BMI | 5.9±2.4 | 5.3±2.0 |
| Fitness (h/week) | 2.1±2.0 | 4.9±1.8 |
| fat mass (KG) | 26.8±11.9 | 26.6±9.8 |
| % fat | 46.4±11.6 | 41.2±7.4 |
| FFM (KG) | 29.8±9.1 | 36.4±7.8 |
| Waist/Height | 0.6±0.1 | 0.5±0.1 |
| Waist/ Hip | 0.9±0.1 | 0.8±0.1 |
Height SD score (SDS), body mass index SDS, total fat mass did not change from phase 1 to phase 2 however Percentage of fat mass decreased
significantly.
| Thyroid Function | Phase 1 | Phase 2 |
| THS (mU/l) | 2.8±1.7 | 2.2±0.9 |
| FT4 | 10.8±2.2 | 10.7±1.9 |
| FT3 | 4.4±1.3 | 3.9±1.1 |
| Thyroid volume (SDS) | –0.5±0.8 | –0.5±1 |
Changes in thyroid function can be observed as levels of FT3 & FT4 decrease back to normal range compared to changes in thyroid structure which were thought to be fairly insignificant however they were still present, along with other positive correlations to lifestyle intervention such as insulin sensitivity and body composition improvements due to decrease in fat mass and a significant decrease in waist/height measurements and waist/hip despite there being little change in total weight.

## What conclusions can we take from this research?

* Overall changes in thyroid structure were thought to be insignificant however they still occurred.
* regardless of changes in weight status children with lifestyle intervention reported changes in homeostasis model assessment for insulin resistance and in adiponectin that were associated with loss of fat mass.
* This establishes that thyroid structure and function can be added to the list of health benefits correlated in the results with early obesity intervention and weight loss in children.
* This research supports studies focused around increased sedentary behavior in children with increasing levels of screen time now taking place and its negative effects, further highlighting the importance for kids to remain active during this crucial growth and development stage.

## Practical advice

* The study is not very specific in how the intervention took place, what exercise was involved or dietary requirements throughout the study. In future a more specific intervention with a set out diet plan and exercise criteria ( IE.20 mins vigorous PA a day), may make results more consistent.
* The children were all diagnosed with simple obesity, other syndrome, organic, and hormonal causes having been excluded from the study and non showed signs of having diabetes or thyroid autoimmunity, so this intervention cannot reliably be applied to those thought to suffer from more than simple obesity.
* Future research might benefit from looking at the effect of lifestyle intervention on those who are already suffering from chronic disease or other population groups such as the elderly population, and whether the same effects on thyroid structure and function can be observed during weight loss.

## Further information/resources

* the Journal of Endocrinological Investigation Issue 3, pp 281–285 .
* Function and Structure Are Affected in Childhood Obesity
* changes in thyroid structure and function
* hormones before and after weight loss in obesity
* Function and Structure Are Affected in Childhood Obesity
* Influences of obesity and weight loss on thyroid hormones

## References

* ↑ https://www.webmd.com/women/picture-of-the-thyroid#1
* 1 2 3 4 5 Radetti, G., Longhi, S., Baiocchi, M. et al. J Endocrinol Invest (2012) 35: 281. https://doi.org/10.3275/7763>
* ↑ https://www.bmj.com/about-bmj/resources-readers/publications/epidemiology-uninitiated/7-longitudinal-studies >
* ↑ Giorgio Radetti, Wolfgang Kleon, Fabio Buzi, Claudio Crivellaro, Lucia Pappalardo, Natascia di Iorgi, Mohamad Maghnie, Thyroid Function and Structure Are Affected in Childhood Obesity, The Journal of Clinical Endocrinology & Metabolism, Volume 93, Issue 12, 1 December 2008, Pages 4749–4754, https://doi.org/10.1210/jc.2008-0823
* ↑ Chrousos GP. The hypothalamic-pituitary-adrenal axis and immune-mediated inflammation. N Engl J Med 1995, 332: 1351-62.