A number of studies have shown that tobacco use is a significant factor in miscarriages among pregnant smokers, and that it contributes to a number of other threats to the health of the fetus. It slightly increases the risk of neural tube defects.

Environmental tobacco smoke exposure and maternal smoking during pregnancy have been shown to cause lower infant birth weights.

Studies have shown an association between prenatal exposure to environmental tobacco smoke and conduct disorder in children. As well, post-natal tobacco smoke exposure may cause similar behavioral problems in children.

Women who smoke have about a 50% higher chance of giving birth to a child with behavioral disorders, such as ADHD, but a recent study in a book called "Attention Deficit Disorder: A Different Perception" overturns this, saying that ADHD is a genetic trait. Proof of this comes from a study showing that the people with ADHD had higher levels of certain hormones, as Thom Hartman explains with the hunter vs. farmer hypothesis.

Studies suggest that smoking decreases appetite, but did not conclude that overweight people should smoke or that their health would improve by smoking. This is also a cause of heart diseases. Smoking also decreases weight by overexpressing the gene AZGP1 which stimulates lipolysis.

Smoking causes about 10% of the global burden of fire deaths, and smokers are placed at an increased risk of injury-related deaths in general, partly due to also experiencing an increased risk of dying in a motor vehicle crash.

Smoking increases the risk of symptoms associated with Crohn's disease (a dose-dependent effect with use of greater than 15 cigarettes per day). There is some evidence for decreased rates of endometriosis in infertile smoking women, although other studies have found that smoking increases the risk in infertile women. There is little or no evidence of a protective effect in fertile women. Some preliminary data from 1996 suggested a reduced incidence of uterine fibroids, but overall the evidence is unconvincing.

Current research shows that tobacco smokers who are exposed to residential radon are twice as likely to develop lung cancer as non-smokers. As well, the risk of developing lung cancer from asbestos exposure is twice as likely for smokers than for non-smokers.

New research has found that women who smoke are at significantly increased risk of developing an abdominal aortic aneurysm, a condition in which a weak area of the abdominal aorta expands or bulges, and is the most common form of aortic aneurysm.

Smoking leads to an increased risk of bone fractures, especially hip fractures. It also leads to slower wound-healing after surgery, and an increased rate of postoperative healing complication.

Regular consumption of alcohol is associated with an increased risk of gouty arthritis and a decreased risk of rheumatoid arthritis. Two recent studies report that the more alcohol consumed, the lower the risk of developing rheumatoid arthritis. Among those who drank regularly, the one-quarter who drank the most were up to 50% less likely to develop the disease compared to the half who drank the least.

The researchers noted that moderate alcohol consumption also reduces the risk of other inflammatory processes such as cardiovascualar disease. Some of the biological mechanisms by which ethanol reduces the risk of destructive arthritis and prevents the loss of bone mineral density (BMD), which is part of the disease process.

A study concluded, "Alcohol either protects from RA or, subjects with RA curtail their drinking after the manifestation of RA". Another study found, "Postmenopausal women who averaged more than 14 alcoholic drinks per week had a reduced risk of rheumatoid arthritis..."

Chronic excessive alcohol abuse is associated with a wide range of skin disorders including urticaria, porphyria cutanea tarda, flushing, cutaneous stigmata of cirrhosis, psoriasis, pruritus, seborrheic dermatitis and rosacea.

A 2010 study concluded, "Nonlight beer intake is associated with an increased risk of developing psoriasis among women. Other alcoholic beverages did not increase the risk of psoriasis in this study."

A few studies have indicated an increased risk of neuroblastoma with use of alcohol during pregnancy.

"Moderate alcohol consumption was associated with a lower risk of renal cell cancer among both women and men in this pooled analysis" "This pooled analysis found an inverse association between alcohol drinking and RCC. Risks continued to decrease even above eight drinks per day (i.e. >100 g/day) of alcohol intake, with no apparent levelling in risk."

A study concluded, "Results from our prospective cohort study of middle-aged and elderly women indicate that moderate alcohol consumption may be associated with decreased risk of RCC." Researchers who conducted a study in Iowa reported that "In this population-based case-control investigation, we report further evidence that alcohol consumption decreases the risk of RCC among women but not among men. Our ability to show that the association remains after multivariate adjustment for several new confounding factors (i.e., diet, physical activity, and family history) strengthens support for a true association.

Another study found no relationship between alcohol consumption and risk of kidney cancer among either men or women.

A Finnish study concluded, "These data suggest that alcohol consumption is associated with decreased risk of RCC in male smokers. Because most of the risk reductions were seen at the highest quartile of alcohol intake and alcohol is a risk factor for a number of cancers particularly among smokers, these data should be interpreted with caution." "Our data suggest an inverse association between alcohol intake and risk of renal cell cancer…" Compared with nondrinkers, men who drank one or more drinks per day had a 31% lower risk of kidney cancer among 161,126 Hawaii-Los Angeles Multiethnic Cohort participants.

Having a particular genetic variant (A-allele of ADH1B rs1229984) is associated with non-drinking and lower alcohol consumption. This variant is also associated with favorable cardiovascular profile and a reduced risk of coronary heart disease compared to those without the genetic variant, but it is unknown whether this may be caused by differences in alcohol consumption or by additional confounding effects of the genetic variant itself.

The International Agency for Research on Cancer of the World Health Organization has classified alcohol as a Group 1 carcinogen.

While little detailed genetic research has been done, it has been shown that alcoholism tends to run in families with possible involvement of differences in alcohol metabolism and the genotype of alcohol-metabolizing enzymes.

Infants exposed to smoke, both during pregnancy and after birth, are found to be more at risk of sudden infant death syndrome (SIDS).

Studies indicate that smoking during pregnancy increases the likelihood of offspring beginning to smoke at an early age.

Studies have shown that heavy drinkers put themselves at greater risk for heart disease and developing potentially fatal cardiac arrhythmias. Excessive alcohol consumption can cause higher blood pressure, increase cholesterol levels and weakened heart muscles. Studies have shown that moderate wine drinking can improve the balance of low-density lipoprotein (LDL or "bad" cholesterol) to high-density lipoprotein (HDL "good" cholesterol), which has been theorized as to clean up or remove LDL from blocking arteries. The main cause of heart attacks and the pain of angina is the lack of oxygen caused by blood clots and atheromatous plaque build up in the arteries. The alcohol in wine has anticoagulant properties that limits blood clotting by making the platelets in the blood less prone to stick together and reducing the levels of fibrin protein that binds them together.

Professional cardiology associations recommend that people who are currently nondrinkers should not start drinking alcohol.

The primary risk factor for COPD globally is tobacco smoking. Of those who smoke, about 20% will get COPD, and of those who are lifelong smokers, about half will get COPD. In the United States and United Kingdom, of those with COPD, 80–95% are either current smokers or previously smoked. The likelihood of developing COPD increases with the total smoke exposure. Additionally, women are more susceptible to the harmful effects of smoke than men. In nonsmokers, secondhand smoke is the cause of about 20% of cases. Other types of smoke, such as, marijuana, cigar, and water-pipe smoke, also confer a risk. Water-pipe smoke appears to be as harmful as smoking cigarettes. Problems from marijuana smoke may only be with heavy use. Women who smoke during pregnancy may increase the risk of COPD in their child. For the same amount of cigarette smoking, women have a higher risk of COPD than men.

Tobacco smoke is a known carcinogen. Workers in the hospitality industry may be exposed to tobacco smoke in the workplace, especially in environments like casinos and bars/restaurants.

Intense and prolonged exposure to workplace dusts, chemicals, and fumes increases the risk of COPD in both smokers and nonsmokers. Workplace exposures are believed to be the cause in 10–20% of cases. In the United States, they are believed to be related to more than 30% of cases among those who have never smoked and probably represent a greater risk in countries without sufficient regulations.

A number of industries and sources have been implicated, including high levels of dust in coal mining, gold mining, and the cotton textile industry, occupations involving cadmium and isocyanates, and fumes from welding. Working in agriculture is also a risk. In some professions, the risks have been estimated as equivalent to that of one-half to two packs of cigarettes a day. Silica dust and fiberglass dust exposure can also lead to COPD, with the risk unrelated to that for silicosis. The negative effects of dust exposure and cigarette smoke exposure appear to be additive or possibly more than additive.

Polycyclic aromatic hydrocarbons (PAHs), fused-ring chemicals formed during the combustion of fossil fuels, are metabolized by the cytochrome P450 complex to highly reactive carbocations, which can mutate DNA and cause cancer. Workers may be exposed to PAHs while working in a foundry, in the roofing industry, or due to environmental tobacco smoke.

Diet and lifestyle are major factors thought to influence susceptibility to many diseases. Drug abuse, tobacco smoking, and alcohol drinking, as well as a lack of or too much exercise may also increase the risk of developing certain diseases, especially later in life. Between 1995 and 2005 813,000 Australians were hospitalised due to alcohol

In many Western countries, people began to consume more meat, dairy products, vegetable oils, tobacco, sugary foods, Coca-Cola, and alcoholic beverages during the latter half of the 20th century. People also developed sedentary lifestyles and greater rates of obesity. In 2014 11.2 million Australians were overweight or obese Rates of colorectal cancer, breast cancer, prostate cancer, endometrial cancer and lung cancer started increasing after this dietary change. People in developing countries, whose diets still depend largely on low-sugar starchy foods with little meat or fat have lower rates of these cancers. Causes are not just from smoking and alcohol abuse. Adults can develop lifestyle diseases through behavioural factors that impact on them. These can be unemployment, unsafe life, poor social environment, working conditions, stress and home life can change a person’s lifestyle to increase their risk of developing one of these diseases.

Occupational exposure to chemicals, dusts, radiation, and certain industrial processes have been tied to occupational cancer. Exposure to cancer-causing chemicals, also called Carcinogens, may cause mutations that allow cells to grow out of control, causing cancer. Carcinogens in the workplace may include chemicals like anilines, chromates, dinitrotoluenes, arsenic and inorganic arsenic compounds, beryllium and beryllium compounds, cadmium compounds, and nickel compounds. Dusts that can cause cancer leather or wood dusts, asbestos, crystalline forms of silica, coal tar pitch volatiles, coke oven emissions, diesel exhaust and environmental tobacco smoke. sunlight; radon gas; and industrial, medical, or other exposure to ionizing radiation can all cause cancer in the workplace. Industrial processes associated with cancer include aluminum production; iron and steel founding; and underground mining with exposure to uranium or radon.

Other factors that play a role in cancer include:

- Personal characteristics such as age, sex, and race

- Family history of cancer

- Diet and personal habits such as cigarette smoking and alcohol consumption

- The presence of certain medical conditions or past medical treatments, including chemotherapy, radiation treatment, or some immune-system suppressing drugs.

- Exposure to cancer-causing agents in the environment (for example, sunlight, radon gas, air pollution, and infectious agents)

Co-carcinogens can be a lifestyle like cigarette-smoking, alcohol-drinking or even areca nut tobacco-chewing, which is an Asian tradition, because those activities promote the cytopathic effect (CPE). Also, some virus are co-carcinogens like Herpesviruses, Epstein–Barr virus (EBV) and human herpesvirus 4 (HHV-4) Epstein–Barr virus destroy immune system for human body and then increase the risk of cancer such as Hodgkin’s lymphoma and human immunodeficiency virus because they cause a long term-chronic inflammation for lymphocytes and epithelial cells. Moreover, Over intake beta carotene for a long period of time increased the risk of lung cancer, prostate cancer and many other kind of malignant tumor for cigarette smoker and worker having high contact with asbestos. Generally, co-carcinogen can be irregular eating habits and disease virus and co-carcinogen not only help cancer cell make malignant tumor but also increase the risk of cardiovascular disease and mortality rate.

An estimated 48,000 cancers are diagnosed yearly in the US that come from occupational causes; this represents approximately 4-10% of total cancer in the United States. It is estimated that 19% of cancers globally are attributed to environmental exposures (including work-related exposures).