Differential Effects of Exercise on the Lipid Profile of Normogycemic Offspring of T2DM Patients in Sagamu, South West Nigeria

1. Introduction

Diabetes mellitus, commonly known as diabetes, is a disorder of intermediary carbohydrate, protein and lipid metabolism. It is characterized by hyperglycemia, glucosuria, polydipsia, polyuria, polyphagia and weight loss. It is usually accompanied by secondary alterations in glucose, fat and protein metabolism, leading to various biochemical disorders. It is characterized by peripheral insulin resistance, impaired regulation of hepatic glucose production with declining β-cell function and consequently leading to β-cell failure (Bacha et al, 2010). Type 2 Diabetes Mellitus (Type 2DM) is characterized by a combination of peripheral insulin resistance with inadequate insulin secretion by pancreatic beta cells. Insulin resistance has been associated with elevated levels of free fatty acids and pro-inflammatory cytokines in plasma, leading to decreased glucose transport into muscle cells, elevated hepatic glucose production, and pronounced breakdown of fat. Researchers have found that obesity and diabetes are inter-connected. Many people who are obese are at high risk of developing T2DM, particular if a close family member is affected with T2DM. Researchers have not yet discovered a specific gene that causes obesity although, various genes are considered to play a role. There seems to be a connection between abdominal fat and diabetes, hence anything that will decrease abdominal fat will likely reduce diabetes (Taiwo et al 2017). Exercise has been known to ameliorate the effects of diabetes by improving insulin sensitivity and lipid profile. Offspring of T2DM have greater chance of developing diabetes mellitus (Fegan et al, 1998). Insulin resistance is one of the pathophysiologic mechanisms for the development and sustenance of T2DM (Gulli et al, 1992). It is the aim of this work is to study the effect of exercise on lipid profile in normoglycemic offspring of T2DM patients.

2. Method

The study involved purposive selection of 100 normoglycemic offspring of T2DM patients attending Diabetic clinic of Olabisi Onabanjo Teaching Hospital, Sagamu. and 100 offspring of normotensive persons living in Sagamu aged between 25 and 50 years. The blood glucose was measured using standard method in order to assert that they are normoglycemic offspring. The subjects had to go through exercise procedure using Tummy trimmer exercise apparatus.

Tummy trimmer, a portable lightweight equipment was selected for the study. It is an in-door anaerobic equipment. It is compact and can fit right in the subject’s brief case.

During each phase of exercise the Tummy trimmer, a portable lightweight equipment, is held at the two handles and the soles of the two feet are put inside the pedal rest while the subject assumes different positions. The subject will then pull the tummy trimmer’s spring towards himself or herself either while lying flat or sitting up on the floor or carpeted hard surface.

Subject sits up with leg straight, leans his or her body backwards until completely lying back with head on floor. He/she returns to sitting position in harmonic fashion. The subject was advised to start slowly and work up to repetitions as she/he feel comfortable with harmoniously.

The subject was advised to lie flat on floor, extend his/her legs straight up in the air. He will be keeping his/her back on the floor and raises lower legs without bending them. The subject was advised to sit erect with legs straight, he/she raise handle to tummy height using arms only.

Finally, subject was advised to lie flat on the floor while he/she bends knees up to his/her chest. He/She makes a circular motion pushes their feet up and then round towards the floor again. The different positions were observed for exercise period of 30 to 40 minutes (a video clip of the exercise procedure was shown to the subject before the commencement of the exercise). Safety Warnings were given to the subject as follows:(1) He/She should not use the equipment while standing (2) Equipment should be used only with sneakers or bare-foot. (3) He/She should not let the unit slip off his/her feet (4) He/She should not allow the spring to stretch beyond 105centimeters.

Each subject was advised: (1) He/She to undergo the 4 phases of exercise between 30 and 40 minutes daily (either in the mornings or evenings). (2) He/She to contact the researcher on cell phone anytime when he/she has any problems with the unit. (3) There were regular cell phone calls made to each of the subjects by the research assistant to ensure compliance with exercise schedule. (4) The research assistant called them on cell phone and sent s.m.s (Short Message Service) to them to keep return appointments every four weeks. This was done one or two days before appointment schedule.

Determination of Lipid Profile Lipid Profile was determined by following the protocol of Trinder, (1969 as described by Ekor, Osonuga, Odewabi and Oritogun (2010) (Burns et al, 2001). Principle Total cholesterol level was measured spectrophotometrically using standard laboratory supplied by BIOLABO, France. Cholesterol esters in the presence of cholesterol esterase cholesterol and free fatty acids are separated. The cholesterol formed reacts with oxygen in the presence of cholesterol oxidase to form cholesten-4-one-3 and hydrogen peroxide. The hydrogen peroxide formed reacts with phenol and 4-amino-antipyrine in the presence of peroxidase to give aminoneimine (pinkish in colour) and water. The intensity of the pink/red colour formed is proportional to the cholesterol concentration. The procedure employed was as follows: The reagent was prepared by adding 5ml of the buffer (1.75mool/L Amino-2-methyl-2-propanol-1) to 5ml of the Chromogen mixture (76umol/L 0-Cresolphtalein Complexon, 3.36mmol/L/L 8 – Hydroxy-Quinoline, 25mmol/L HCI) and allowed to stand for an hour at room temperature. The reagent solution was prepared by adding equal volumes of the buffer and 5mmol/L Chloro-4-phenol) and the enzyme mixture (100U/L Cholesterol oxidase, 70U/L Cholesterol esterase, 1200U/L peroxidase, 2mmol/L Cholic acid Sodium salt, 0.3mmol Amino antipyrine) and allowed to stand for 5 – 10 minutes while mixing gently at room temperature. To 10µL of each test sample or standard (5.17mmol/L Cholesterol) was added 1ml of the reagent mixture. This was incubated at 37oC for 5 minutes. The absorbance of the mixture was taken against the blank at a wavelength of 500nm. The blank was made up of 10µL of distilled water and 1ml of the reagent mixture. The cholesterol concentration was determined as follows Total cholesterol concentration (mg/dl) = Absorbance sampleX Standard concentration Absorbance standard HDL cholesterol level was measured spectrophotometrically using standard lab kits supplied by BIOLABO, France. Low density lipoproteins (LDL) contained in serum are precipitated by addition of phosphotungstic acid and magnesium chloride. High density lipoproteins (LDL) which remains in the supernatant (obtained after centrifugation) react with the cholesterol reagent and proportionally with the cholesterol standard. The procedure followed was as follows: equal volumes of the serum and reagent mixture (13.9mmol/L phosphotungstic acid and 570mmol/L magnesium chloride) were mixed together and allowed to stand for 10 minutes at room temperature. The reaction mixture was then centrifuged for 10 minutes at 4000rpm to get a clear supernatant. This supernatant was used as sample to get the HDL cholesterol concentration in the serum sample. 1000ul of the Cholesterol reagent was added to test tubes labeled blank, standard and sample containing 50µl water, 50µl of the cholesterol standard and 50µl of the sample respectively. This was well mixed and incubated for 10mins at 37oC. The absorbance of the end sample against the blank was taken at 505nm. HDL cholesterol concentration (mg/dl) = Absorbance sampleX Standard concentration Absorbance standard Triglycerides level was measured spectrophotometrically using standard tab kits supplied BIOLABO, France Triglycerides in the presence of lipase form glycerol free fatty acids. Glycerol formed reacts reversibly with adenosine triphosphate (ATP) in the presence of glycerol lipase to form glycerol – 3 – phosphate and ADP. The glycerol 3 phosphate also reacts reversibly with oxygen in the presence of glycerol -3- phosphate oxidase to form dihydroxyacetone phosphate and hydrogen peroxide. The hydrogen peroxide then reacts with chlorophenol and amino antipyrine in the presence of peroxidase to form quinoneimine (pink) and water. The intensity of the pink/red colour formed is proportional to the triglyceride concentration. The reagent solution was prepared by adding equal volumes of the buffer (3.5mmol/Lchloro-4-phenol, 6mmol/L Magnesium chloride 100mmol/L PIPES) and the enzyme mixture 500U/I Lipase, 1800U/I peroxidase, 400U/I Glycerol 3- phosphate oxidase, 1000U/I Glycerol (lipase. 0.30mmol 4 Amino antipyrine. 1.72mmol/I Adenosine triphosphate Na) and allowed to stand for 5 – 10minutes. To 10µL of each test sample of standard (Glycerol 200mg/dl) was added 1mI of the reagent mixture. This was incubated at 37oC for 5minutes. The absorbance of the mixture was taken against the blank at a wavelength of 500nm. The blank was made up of 10µL of distilled H20 and 1ml of the reagent mixture. The triglyceride concentration was determined as follows. Triglyceride concentration (mg/dl) = Absorbance sample X Standard concentration Absorbance standard.

Ethical Approval and Informed Consent Ethical clearance for the study was obtained from the Committee on Human Research publication and Ethics of the School of Olabisi Onabanjo University teaching Hospital (OOUTH), Sagamu (with number HREC/OOU/0030/2024). All participants (200) of this study signed an informed consent form, in accordance to the committee regulations, before answering the questionnaire, blood pressure measurement and taking blood samples. Statistical analysis was carried out by using student test. The data obtained was analysed using computer statistical programme package SPSS version 15.0 Probability value of P less than 0.05 was considered statistically significant.

3. Results

Table 1: Variations in the anthropometric parameters, FBS and lipid profile at baseline between the ODP and OCP

* Significant at p< 0.05

ODP – Offsprings of diabetic parent

OCP - Offsprings of control parent

There were one hundred participants (100) in each study group and control group. The mean age of  ODP and OCP were 26.02 years+5.14 and 26.11years+5.92 respectively. There were 50 males 50 females in each group. The mean height in ODP and OCP were 1.63m+0.09 and1.65m+0.07 respectively (p=0.066). The mean weight in ODP and OCP were 64.10kg+7.77 and 61.01kg+6.24 (p=0.002*). The mean BMI in ODP and OCP were 24.13kgm2+3.09 and 22.34kgm2+2.49(p=0.001*). The mean FBS in ODP and OCP were 91.12mg/dl+10.07 and 70.82mg/dl+11.83 (p=0.001*). The mean TC in ODP and OCP were 150.52mg/dl+45.56 and 158.35mg/dl+37.11 (p=0.184) The mean TG in ODP and OCP were 100.25mg/dl+40.11 and 70.58mg/dl+21.57 (p=0.001*) The mean HDL in ODP and OCP were 44.73mg/dl+13.01 and 56.57mg/dl+11.10 (p=0.001*) The mean LDL in ODP and OCP were 80.93mg/dl+36.69 and 87.25mg/dl+34.86 (p=0.001*). The mean mean arterial BP in  ODP and OCP were 58.70mmHg+10.10 and 57.24mmHg+8.51 (p=0.269).

Table 2: Variations in the anthropometric parameters, FBS, lipid profile and hypertensive parameters during 6 months follow-up in ODP

In ODP study group, the mean weight reduced from 64.10kg + 7.77 at baseline to 52.64kg+6.44 after six months of exercise (p=0.001). The mean BMI significantly reduced from 24.13kg/m2 + 3.09 at baseline to 19.83kg/m2+2.64 after six months of exercise (p=0.001). The mean FBS significantly reduced from 91.12mg/dl + 10.27 at baseline to 76.64mg/dl+8.67 after six months of exercise (p=0.001). The mean TC significantly reduced from 150.52mg/dl + 45.56 at baseline to 127.78mg/dl+38.50 after six months of exercise (p=0.001). The mean TG significantly reduced from 100.25mg/dl + 40.11 at baseline to 84.90mg/dl+34.13 after six months of exercise. The mean HDL significantly increased from 44.73mg/dl + 13.01 at baseline to 58.95mgdl+17.25 after six months of exercise(p=0.001). The mean LDL significantly reduced from 80.93mg/dl + 36.69 at baseline to 68.22mg/dl+30.80 after six months of exercise (p=0.001). The mean Mean Arterial Pressure significantly reduced from 58.70mmHg + 10.10 at baseline to 50.06mmHg+8.69 after six months of exercise(p=0.001).

Table 3: Variations in the anthropometric parameters, FBS, lipid profile and hypertensive parameters during 6 months follow-up in OCP

Table 3: Variations in the anthropometric parameters, FBS, lipid profile and hypertensive parameters at baseline and 6 months follow-up in ODP and OCP

* Significant at p< 0.05

* Significant at p< 0.05

In OCP control group, the mean weight reduced from 61.01kg + 6.24 at baseline to 56.79kg+6.18 after six months of exercise(p=0.001). The mean BMI significantly reduced from 22.34kg/m2 + 2.49 at baseline to 20.80kg/m2+2.41 after six months of exercise (p=0.001). The mean FBS significantly reduced from 70.82mg/dl + 11.83 at baseline to 65.58mg/dl+10.91 after six months of exercise (p=0.001). The mean TC significantly reduced from 158.35mg/dl + 37.11 at baseline to 148.26mg/dl+34.77 after six months of exercise (p=0.001). The mean TG significantly reduced from 70.58mg/dl + 21.57 at baseline to 65.61mg/dl+19.97 after six months of exercise (p=0.001). The mean HDL significantly increased from 56.57mg/dl + 11.10 at baseline to 65.20mgdl+12.18 after six months of exercise(p=0.001). The mean LDL significantly reduced from 87.25mg/dl + 34.86 at baseline to 81.02mg/dl+32.54 after six months of exercise (p=0.001). The mean Mean Arterial Pressure significantly reduced from 57.24mmHg + 8.51 at baseline to 52.63mmHg+7.96 after six months of exercise(p=0.001).

Figure 1: Variation in mean weight in ODP and OCP over the periods of study.

Figure 2: Variation in mean BMI in ODP and OCP over the periods of study.

Figure 3: Variation in mean FBSin ODP and OCP over the periods of study.

Figure 4: Variation in mean TC in ODP and OCP over the periods of study.

Figure 5: Variation in mean TG in ODP and OCP over the periods of study.

Figure 6: Variation in mean HDL in ODP and OCP over the periods of study.

Figure 7: Variation in mean LDL in ODP and OCP over the periods of study.

Figure 8:Variation in mean SBP in ODP and OCP over the periods of study.

Figure 9: Variation in mean maBP in ODP and OCP over the periods of study.

Figure 10: Variation in mean PP in ODP and OCP over the periods of study.

4. Discussion

In this study, lipid profile is the main parameter which was tested in the normoglycemic offspring of type 2 diabetes mellitus patients. Diabetes mellitus is a disorder of intermediary carbohydrate, protein and lipid metabolism associated with high blood glucose level (hyperglycemia) and presence of glucose in the urine (glucosuria). It is associated in many cases by secondary alteration in fat and protein metabolism resulting in an array of biochemical disorders and diabetes mellitus in family members of individuals with type 2 diabetes mellitus (Galbo et al, 1988).

 However, it will be instructive to compare these results with the one done by Borghout et. al., 1999 using bicycle ergometer as instrument apparatus to measure lipid profile in normoglycemic offspring of T2DM. Furthermore, regular exercise has been shown to decrease fasting triglyceride concentration in some patients (Fegan et al, 1998). Hannele et al, 1989 studied the effect of body composition and maximal aerobic power on insulin sensitivity. They found that body sensitivity to insulin and lipid profile are directly related to the muscle mass and inversely proportional to adiposity. They also reported that one factor contributing to reduce in insulin sensitivity is obesity which occurred during physical inactivity. Therefore, in this present study, improvement in lipid profile after six months of exercise confirms the importance of physical activity in improving lipid profile in offspring of T2 diabetes patients. Insulin resistance may play a pivotal role in the development and sustanance of diabetic dyslipedemia by influencing several factors such as insulin resistance and type 2 diabetes, promoted efflux of free fatty acids into the liver (Boden et al, 1997, Kelly et al, 1994). Hepatic lipase activity is responsible for hydrolysis of phospholipids in LDL and HDL particles and leads to smaller and denser LDL particles and reduction in HDL (Tan et al, 1995, Zambon et al, 1993) and so leading to rise in serum lipids which is seen in obesity.

 Lifestyle interventions such as diet, physical activity, weight loss, and stopping smoking are integral part of any diabetes management plan. Epidemiologic and intervention studies have shown great improvements in the features of diabetic dyslipaedemia such as medical nutrition therapy and physical activity (Kraus et al, 2002, Williams et al, 1990). Exercise is a major therapeutic modality in the management of diabetes mellitus (Laaksonen et, al, 2000). Exercise training has been known to be advantageous in type 2 diabetes mellitus by improving lipid profile (Ibanez et al, 2005), and regular exercise can strengthen antioxidant defenses and may decrease oxidative stress (Kim et al, 1996). Exercises including yoga postures have been shown to play a role in abating type 2 diabetes (Sahay et al, 2002). The yoga postures are slow rhythmic movements which emphasize the stimulation of the organs and glands by easy bending and extensions which do not overstimulates muscles but focus on glandular stimulation (Nayak et al, 2004). A major benefit of non-exhaustive exercise such as yoga is to induce a mild oxidative stress that promote the expression of certain antioxidant enzymes. This is associated with the activation of redox-sensitive signaling pathways (Reid et al, 2001). Obesity, as a result of inactivity in combination with increase food intake, plays a key role in the development of pancreatic beta-cell dysfunction as well as insulin resistance. Various mechanisms mediating this interaction have been identified. It is now well established that a number of circulating hormones, cytokines, and metabolic fuels, such as non-esterified fatty acids (NEFAs), are being released by adipose tissue which can modulate insulin action. An increased mass of stored triglyceride, especially in visceral or deep subcutaneous adipose depots, leads to large adipocytes that are themselves resistant to the ability of insulin to reduce lipolysis. This leads to increased release and circulating NEFA and glycerol levels, both of which aggravate insulin resistance in skeletal muscle (Boden, 1997) and in the liver (Kabir et al, 2005 Peterson, et al, 2005 Ryysy et al, 2000). Ectopic fat storage in hepatocytes, so-called intrahepatic lipids (IHL), has also been associated with the development of hepatic insulin resistance (Ko et al, 2017) and hepatic inflammation, producing non-alcoholic fatty liver disease (Shamizadeh et al, 2016). Our study, however, examines the effect of exercise on the lipid profile of offspring of diabetes using tummy trimmer as exercise apparatus.

However, this study examined the effect of six months of exercise using tummy trimmer on TC, HDL‑c, LDL‑c, and TGs in normoglycemic offspring of diabetic patients. Findings from the present study showed a significant decrease in TC, LDL‑c, and TGs and a significant rise in HDL‑c in study group compared to controlled group. The findings of the current study are similar to previous studies that also found significant reduction in TC, LDL‑c, and TGs and significant rise in HDL‑c (Shaw et al, 2009, Tseng et al, 2009) in EG compared to CG. Various studies conducted in diabetic patients and their reports showed that TC, LDL‑c, and TGs were decreased significantly and HDL‑c increased significantly in combined aerobic and resistance exercise subjects (Reid, 2001, Kabir et al, 2005). The findings of these studies agreed with the present study. Moreover, the current study is in agreement with the study of Shaw et al Bazzano et al, 2009), in which LDL‑c decreases significantly and the study of Tseng et al, 2009 and Tokudome et al, 2004 which showed a pronounced reduction in TGs and a significant rise in HDL-c in combined aerobic and resistance exercise training compared to CG. HDL acts as a remover of bad cholesterol in the reverse transport of cholesterol (Samuel et al, 2007). In our study high adherence to exercise (98%) was found and this may be also the possible reason for the improvement of lipid profiles in the study group, hence, this study has valuable clinical significance for the participants of the study hereby improving their lipid profiles.

Regular exercise can significantly improve lipid profiles in the offspring diabetic patients, decreasing levels of total cholesterol (TC) and LDL cholesterol while potentially causing a rise in HDL cholesterol. These positive changes are linked to a reduced risk of cardiovascular disease. The effectiveness of exercise can be affected by factors like duration, intensity, and age of the individual (Samuel et al, 2007).

Although the mechanism of exercise-induced lipid changes is unclear, exercise itself may be responsible for blood lipid consumption hence to decrease lipid levels (Tseng). Mechanisms may be associated with the increased activity of lipoprotein lipase (LPL) - lipoprotein lipase responsible for chylomicrons and VLDL TAG hydrolysis in granules (Calabresi et al, 2010). Most of the catalytically active LPL is situated in the vessel wall and then isolated from the endothelium surface and released in the blood after intravenous injection of heparin (Kobayashi et al, 2007). Therefore, the detected LPL is always in the post-heparin LPL. Ferguson et al, 1998 reported that heavy or prolonged aerobic exercise episodes could significantly boost post-heparin plasma LPL activity, thus promoted LPL-mediated TG hydrolysis. Exercise-induced LPL changes were time-related, for example, LPL mRNA peak level occurred at 4 h after exercise (Kobayashi et al, 2007). Besides, LPL activation rise could last for 24 h after only a 1 h exercise session in individuals with moderate intensity exercise (Seip et al, 1997).

In addition to the traditional mechanisms described above, several other discoveries revealed the mechanisms about exercise changing lipids profile from other aspects. Increased expression of ATP-binding cassette transporter A-1 (ABCA1) in macrophages has a significant effect on RCT, plasma HDL-C formation, and protection against atherosclerosis (Seip et al, 1997).

5. Limitation of the Study

Prospective study over years and inability to measure the lipid profile over long period of time and the other underlying health challenges in the subjects which were not identified at the time of study may be cofounding variables. This is an interesting issue for future investigations. However, continuous research is needed to validate our findings.

6. Conclusion

There is reduction in lipid profiles in all the participants who engaged in exercise. The reduction is more in the study group. The disturbances in lipid profile between the control and study subjects will require continuous monitoring of same in study to prevent cardiovascular events. Hence, the study subjects need to be watchful of their lipid profile so that they engaging in regular exercise in order not to cause disturbances of their lipid levels. This can delay the onset of development of T2DM in the future.

Consent for publication: All the authors gave consent for the publication of the work under the creative commons Attribution-Non-Commercial 4.0 license.

Competing interests: The authors declare no potential conflicts of interest concerning the research, authorship, and/or publication of this article

Funding: The author(s) received no financial support for the research, authorship, and/or publication of this article.

Acknowledgments: We thank everybody who has one way or the other contributing to the success of this article.

Declaration of Generative AI and AI-assisted Technologies: This study has not used any generative AI tools or technologies in the preparation of this manuscript.