Cause - Effect
The following text is an example of a cause-effect format. It is an excerpt from an article in "The Conversation” by Kaye Roberts-Thomson from the University of Adelaide, and you can access the full article here. Mouse over the page to see how this text is structured.
Bad oral health can have a significant negative impact on people’s quality of life. It can also affect other diseases that they may be suffering. But whether oral ill-health causes general health problems depends on what disease you’re talking about.
People with untreated oral and dental diseases can experience severe pain, loss of sleep, inability to eat certain foods, time off work or school and embarrassment about their appearance. These diseases can accelerate the progress and severity of other illnesses, which makes it even more important that we do all we can to ensure everyone has access to affordable dental care.
The oral disease most frequently associated with medical conditions is chronic periodontal disease, which is the result of inflammation of the tissues surrounding the tooth affecting the gum, the ligaments and the bone. It’s caused by a bacterial infection and other factors, such as smoking.
In its most severe forms, periodontal disease can cause loss of the bone that supports the tooth, resulting in the tooth becoming loose. It can even cause tooth loss.
The strength of the relationship between periodontal disease and general health varies with the medical condition under investigation. The strongest evidence for such a link is between periodontal disease and diabetes.
Periodontal disease and diabetes
Epidemiological studies have confirmed that patients with diabetes (both type 1 and type 2) are more susceptible to periodontal disease. The extent of the risk relates to the duration and control of their diabetes – periodontal disease is likely to increase markedly when diabetes is poorly controlled.
Diabetes, in turn, leads to more rapid and severe progression of destructive periodontitis, increasing the risk of greater severity at least twofold. It essentially doubles the rate of periodontal disease progression.
Essentially, research suggests the relationship between periodontal disease and diabetes goes both ways – not only do people with diabetes have more severe periodontal disease, but periodontal disease may make it more difficult for people who have diabetes to control the condition. (Roberts-Thomson, n.d.)
The first sentence in this paragraph lists the effects of untreated oral and dental diseases: severe pain, loss of sleep etc. The presumed cause (untreated oral and dental diseases) and the effects (severe pain, loss of sleep etc.) are linked by the verb can experience.
The second sentence gives a second effect: the progress and severity of other illnesses. This time the cause (These diseases) and the effect (the progress and severity of other illnesses) are linked by can accelerate. The auxiliary verb can is important because it indicates that these are possible effects which might not always occur in all cases.
Roberts-Thomson, K. (n.d.). How much is general health affected by oral health? Retrieved August 27, 2019, from The Conversation website: http://theconversation.com/how-much-is-general-health-affected-by-oral-health-5858
These two sentences examine the link between periodontal disease and diabetes, as the title of the section states. The two phrases more susceptible to and likely to indicate that the relationship is one of likelihood not certainty. But it's not random; there is measureable relationship between how long a person has had diabetes (duration) and how well the diabetes has been controlled (control), and the risk of having periodontal disease.
The phrase "leads to" is also an indication of a cause - effect link. These three sentences reveal how complex cause - effect relationships can be. They can go "both ways". In this case, the suggestion is that peridontal disease is linked to diabetes and that diabetes makes periodontal disease worse. So we have a circular chain of cause and effect.
There are two more sections in this article. One discusses other diseases influenced by oral or dental problems and the other deals with an important issue in all research: correlation and causation. You should click the link at the top of this page to access the full article.
Cause and effect can be complicated. It is important to be clear about what is a cause and what is an effect.
Often there are clear signal words like cause, effect, resulting in, due to, and so on. So it's easier to understand what is the starting point (the cause) and what is the end point (the result or effect).
But what we are concerned with in these texts is relationships or links between events. Not all relationships are causal; they may be just coincidental (they happened at a similar time or place so we look for a causal link, but it may be just chance that they happened in the same time or place). And sometimes there may be a causal connection but it may work only some of the time because of other complicating factors. In this case it's wise to be cautious and use some hedging language (tends to, may, usually, perhaps, etc.) to indicate our doubt about the precise relationship.
If you are writing about research you will be familiar with ideas of correlation and causation; they are not the same, and correlation does not always indicate causation. The last paragraph in Kay Roberts-Thomson's text (which you should read - click on the link in the introduction) cautions against this.
Students are often asked to write cause and effect texts to demonstrate their ability to use this form of text organisation. But few real texts are based purely on this form. Often, texts are more concerned with mainly causes or mainly effects (depending on the purpose of the text) rather than a mixture of both.
If you are a student of English you need to be careful because some of the cause and effect words are used in ways which a learner may find confusing.
'Cause' is a noun and a verb: a cause (n) is the reason something happens; to cause (v) means to make something happen.
'Effect' is also a noun and a verb: an effect (n) is the result of an action; to effect (v) means to cause (!!!), as in "effect a U-turn", "effect an escape".
'Affect' is a noun and a verb but for our purposes we need only consider the verb, which means to have an influence on or cause something to change.
It is advisable to avoid using 'effect' as a verb; use 'affect' instead until you are thoroughly familiar with their use.
The best way to understand these terms is to read widely and note their use in context.
This section has a title (Periodontal Disease) so we know what the topic is. We can expect to find the causes and effects of this disease here.
These four sentences describe a chain of cause and effect. The first two sentences tell us what causes periodontal disease (bacterial infection and other factors ....), and what the effects or results are (inflammation of the tissues surrounding the tooth ...).
The next two sentences describe what peridontal disease causes (loss of bone....) and what are the consequent effects (tooth becoming loose and possibly lost).
So the chain is: bacterial disease - inflammation of tissues surrounding the tooth .... = periodontal disease - loss of bone that supports the tooth - tooth becomes loose - tooth can be lost.
Again, the word can is important. It tells us that this chain of events is not inevitable. It can be stopped (probably with the correct treatment).
There are many ways of indicating a cause - effect relationship. There are three in these three sentences: "have an impact on", "can affect", and "cause". In the first sentence impact is qualified by "significant" and "negative". So we know right from the first sentence that we are dealing with a serious issue.
Cause and effect texts are all about the relationship or link between the two so we often find these words in these texts. The relationship is not always direct and invariable, as the find sentence points out. In this case it depends on the "medical condition under investigation". But the writer claims that there is a strong causal link "between periodontal disease and diabetes". It's the last comment in this section so it leads smoothly into the next.
The verb "affect" is often used to signal a cause - effect connection. So we know right from the start, in the title, that this is the type of text we are reading. "is .... affected by" is the passive voice. So the question is, how much does oral (dental) health affect (influence) our health in general? This is the question the text addresses.