In general, WIP's 5-year interventional activities in workplaces have been effective in reduction of CVD risk factors; therefore it can be suggested that the prevalence of CVDs among office and factory workers will reduce in the future.
A major CVD risk factor is hypertriglyceridemia, the prevalence of which was significantly reduced in workers of intervention group, while the opposite happened in the control group. This outcome confirms that the nutritional interventions and the efforts to change the food habits were satisfactorily effective. A research on nutritional changes in intervention group revealed that hydrogenated vegetable oils were used significantly less among this group (as compared with control group), while the consumption of fruit and vegetables was increased.12
Similarly, abdominal obesity reduced in workers of intervention group, but rose among the control. group. It is known inappropriate food and insufficient physical activity are two reasons that lead to obesity and as it seems proper changes in workers’ food habits12
, along with stretching exercises at workplace and altering the workers’ routine activities into beneficial ones led to the mentioned improvement in intervention group.
However, it is surprising that the prevalence of low HDL-C was increased among intervention group after the interventions since we know that the most effective factor on HDL-C level is physical activity and an increment in this factor is associated with an increase in HDL-C serum level.13
So, the increased prevalence of low HDL-C and the decreased serum level of HDL-C would probably be related to the significant reduction in Tchol in intervention group because when Tchol is decreased as a result of dietary changes, without any noticeable increment in physical activity, HDL-C level is reduced. Similar results were also obtained in a study conducted by Geil et al. in which only nutritional interventions were implemented.14
But in a study performed by Lan Londe et al., where the nutritional interventions were accompanied with physical activity related interventions, Tchol to HDL-C ratio improved.14
It's worth mentioning that the reduction of TG and Tchol, as a result of interventions, among factory workers indicate the positive effects of nutritional interventions.
Although a small increase in the prevalence of central obesity among both groups existed, the difference was not significant. This shows that population's weight didn't have a considerable change, but their body size and shape were improved; a result which observed among the whole society, too .15
It seems that abdominal obesity changes might be due to dietary changes, and since they were not accompanied with physical activity increment, weight reduction was not observed. On the other hand, the prevalence of smoking also decreased among factory and office workers, which can, in turn, be responsible for BMI increase among them (because we know that the appetite grows after a person quits smoking or smokes less).
As the results of this study suggest, the prevalence of hypertension, in intervention group, didn't change significantly when compared with the control group; the mean value for DBP significantly increased among intervention group, and decreased among the control group. However, SBP changes were in favor of interventions.
One nutritional intervention used in WIP was to educate people to use less salt; restaurant chefs were also told to do the same when cooking.9
Given that hypertension is directly related with salt consumption, the outcomes obviously reflected the effectiveness of interventions. On the other hand, only SBP is directly related with salt consumption, and DBP is associated with peripheral resistance, so, the obtained results seem reasonable. The given data is also in agreement with IHHP results for the whole society.16
Blood sugar increased in two studied groups, but significantly more in intervention group. This may be attributable to the replacement of fats with some starches, or more importantly to age increment especially among intervention group.16
However, changes in FBS levels are not normally considered a major index of intervention effectiveness.
Most office workers have a little physical activity during office hours and spend many hours sitting. Besides, except for a few organizations, most organizations close at 2 p.m., and hence no food is served in them and their staff eat food at home or somewhere out of the workplace. Therefore, most interventions were just educational. As the results of the present study show, among the office workers of intervention group, the prevalence of hypertriglyceridemia and hypercholesterolemia significantly decreased, while the prevalence of low HDL-C was considerably increased. Furthermore, similar to factory workers, interventions led to a significant reduction in the prevalence of abdominal obesity, but didn't cause any noticeable changes in central obesity. Since there was a great dietary change among the office workers, in the intervention group, without any particular effort from the project, it seems that the education level had a substantial effect on the reduction of blood lipids in these people. Moreover, it's usually women who make food, so the more percentage of women working in offices than those working in factories could be another reason for the effectiveness and practicality of the educational programs. Changes in risk factors were similar to those observed in the whole society, which shows that this age group follows the social changes.15
The prevalence of hypertension increased significantly in both intervention and control groups, which is in contrast with the results of our previous report.15
The only significant difference was in case of DBP for which an increase in the intervention group and a decrease in the control group were observed. So it can be inferred that these people didn't change the amount of salt consumption; however, other factors such as regular exercise, smoking, and family history can also affect hypertension.
Considering observed changes among office workers, it could be concluded that the interventions were most effective on food habits, whereas they hadn't an appropriate effect on physical activity.
A clinical study in the U.S. showed that after 2 years of interventions, especially physical activity related educational interventions, weight, blood lipids levels and hypertension were not changed significantly.17
In a similar study in Malaysia, 2 years of workplace interventions made a significant reduction in total cholesterol among the intervention group; HDL-C was reduced in the intervention and the control groups, but this reduction was significantly more in the intervention group; no significant change in TG, FBS and BMI was observed.14
Another experience in Japan indicated that 18 months of comprehensive interventions on office worksites significantly reduced BMI, SBP, Tchol and TG among the intervention group. In addition, when subjects with one special risk factor were considered separately, a significant reduction of BMI, TG and Tchol was also seen in them.18
The results of HIPOP-OHP study, which conducted 4 years of physical activity related interventions in labor worksites, showed a significant increase in HDL-C levels in the intervention group.19
However, worksite chronic disease prevention program suggested that even 6-week or 6-month interventions can increase health knowledge, improve nutrition and physical activity, and also decrease many health risks among the employees .21
Another study indicated that low-intensity; short-term interventions in worksites can significantly improve health behaviors, nutritional knowledge, and decrease SBP in the intervention group. Nevertheless, this study suggested that a longer duration or more intensive intervention may be required to achieve further reduction in risk factors.21
In another experience, just Tchol and HDL-C were reduced significantly after interventions.22
In the interventions conducted in IMPACT study in the USA, a significant reduction in Tchol was seen among hypertriglyceridemic subjects.23
A review article, which reviewed various studies on white European and American factory and office workers, reported a 5-9% reduction in Tchol as a result of worksite nutritional interventions.24
Generally, the present study suggested that worksite interventions would be effective on CVD risk factors. As the scientists believe, management support and the feeling of ownership among the participants are essential for the project effectiveness4
, similarly in this study, the participation of worksite executives and workers contributed to the project's success.
Furthermore, the simultaneous of this project with a number of other interventional projects on different target groups makes those other interventions more effective.
In addition to group educational programs, this project featured some personal counseling for high risk subjects. Research shows that these kinds of interventions have been effective in worksite health promotion .25
Therefore, it can be concluded that WIP, as a practical tool for health promotion among factory and office workers in their worksites, creates tangible changes in people's lifestyle which not only ensures healthy workers, but also leads to a healthy societycells.9
The results of this study which are indicative of relative reducing in negative surface charge of LDL particle in the presence of CRP, are in line with the results of a study conducted by Rufail et al. It is noteworthy that in that study, the result of electrophoresis was obtained only after 2 hours of incubation, but in the present study, this period was extended to 18 hours.19
It can be explained that possibly this protein participates in atherogenesis through a mechanism leading to conformational changes in the semi-oxidized LDL molecule.
The results of this study are consistent with recent studies which have highlighted a kind of relationship and physical binding between CRP and Ox-LDL.7
It is possible that binding of CRP to some areas of the LDL particle (like, phosphocholine moiety) leads to some changes on the surface of this lipoprotein, resulting in reducing of susceptibility of LDL to more oxidation in addition to preparing this modified-lipoprotein for phagocytosis by macrophage receptors.
In the present study, different level of CRP within its physiological range in serum were used to assess the degree to which LDL oxidation would be influenced in progressive concentrations (0 µg/ml, 0.5 µg/ml and 2 µg/ml CRP) because according to previous studies, it has been clearly demonstrated that the elevated level of CRP is related to higher incidence of cardiovascular disease (17, 18, 22). It is notable that the results of some recent studies have shown that vascular endothelial cells are prompted by a number of trigger factors to secrete CRP22
this finding can form a basis for the hypothesis that this protein may be dispatched to the external space, where LDL is invaded by oxidative factors. Also one could hypothesize that LDL, which in the initial stages of oxidation induces CRP secretion, indirectly recalling this protein towards itself to resist invading factors. Based on the result of this study, maybe the processes hypothetically ascribed to CRP be inherently conducive to vascular health and this protein may have antiatherogenic properties by providing relative protection for LDL against oxidation, but it must be borne in mind that it may be possible that, under acute conditions,it act to expedite atherogenesis (such as; cooperation with macrophages to form foam cells). This second hypothesis may be more compatible with the fact that the level of CRP increases during cardiovascular diseases.9